The very first time Cloud and Tifa meet in Final Fantasy VII, it is very clear that the two have some kind of past connection aside from AVALANCHE, which is soon revealed that they are old childhood neighbors and friends from same town of Nibelheim. However, Cloud’s childhood relationship with Tifa involved a crush on her that led to him to join up with SOLIDER in hopes of impressing and getting her to notice him as well as making a promise at the Nibelheim Well to always protect her which is the first thing revealed about their relationship which is told in Tifa's bar, Seventh Heaven. Cloud appears to be her friend as Barret and he and use her bar as AVALANCHE's base of operations, although he is a mercenary so its convenient and keeps him paid. Interestingly though, despite his friendship, his actions and words in the current frame of events indicate a number of occasions where we see Cloud acting quite cold to Tifa, as seen the following passages:


Barret "Don't get no ideas 'bout hangin' on to Shinra."

Cloud "Stayin' with Shinra? You asked me a question and I answered it... that's all."

Cloud "I'm going upstairs. I want to talk about my money."

(Cloud moves to leave. Tifa runs in.)

 

Tifa "Wait, Cloud!"

Barret "Tifa! Let him go! Looks like he still misses the Shinra!"

Cloud "Shut up! I don't care about either Shinra or SOLDIER! But don't get me wrong!”

Cloud “I don't care about AVALANCHE or the Planet for that matter!"

Tifa "Straighten things up with everyone for me."

(Cloud goes back up the elevator and goes to leave. He is followed by Tifa.)

 

Tifa "Listen, Cloud. I'm asking you. Please join us."

Cloud "Sorry Tifa..."

Tifa "The Planet is dying. Slowly but surely it's dying. Someone has to do something."

Cloud "So let Barret and his buddies do something about it. It's got nothin' to do with me."

(He moves to leave)

 

Tifa "So! You're really leaving!? You're just going to walk right out ignoring your childhood friend!?"

Cloud "What...?"

Tifa "You forgot the promise, too."

Cloud "Promise?"


While Cloud ignores Tifa’s request to straighten things up with everyone for her. He also tells her that he doesn’t care about AVALANCHE, and moves to leave three times despite Tifa’s requests for him to stay. Cloud has also forgotten about the Promise when Tifa first brings it up to him. These and similar passages suggest that Cloud is long over his crush on her and they are exclusively comrades and friends as seen in response to her:

Tifa: You remember now? …Our promise?
Cloud: I’m not a hero and I’m not famous. I can’t keep…. the promise.


Despite Cloud's coldness with Tifa, she still cares about him. When Cloud comes back after his first mission we have this following message:


Tifa: You know, I’m relieved you made it back safely.”  
Cloud: What’s with you all of a sudden? That wasn’t even a tough job.
Tifa: I guess not… You were in SOLDIER.”   (Cloud sets down his drink.)  
Tifa: Make sure you get your pay from Barret.

Then again Tifa inquired about Cloud’s well-being:

Tifa: Cloud, are you feeling all right?
Cloud: …yeah… Why?
Tifa:  No reason. You just look a little tired I guess. You’d better go down below.

After the mission, Cloud wants to leave Avalanche because he doesn’t want to have anything to do with their goals. Note that it’s a terrorist organization that is against the world’s most powerful organization ShinRa which Cloud thinks he used to be a SOLIDER in. Not only that, but the jobs are dangerous and involve bombing ShinRa reactors.

Due to his friendship he was convinced otherwise when Tifa reminded him about the promise.

Tifa: So! You’re really leaving!? You’re just going to walk right out ignoring your childhood  friend!?” 
Cloud: What……?

Tifa "You forgot the promise, too."

Cloud "Promise?"


Cloud has two choices but both of them show he cares about what Tifa says despite his coldness. The first choice results to positive affection points from Tifa, while the second has him apologize. It is important to mention that Cloud forgets his childhood in Disc 1, all that he remembers are because of Tifa’s memories which were copied by Jenova cells. So he saw the promise in her perspective. Only in Disc 2 did we learn Cloud’s real perspective- which is to have her notice him due to his childhood crush on her.


In fact, Cloud appears to act like a heartless mercenary until he falls into Aerith's Church and agrees to be her bodyguard. Being around her starts to make him open up about his friends including Tifa and the Planet. It is important to note that although Cloud does not love Tifa he does care for her. As soon as he brings Aerith back to her house he tries to leave. I’m not saying Cloud doesn’t care about Aerith since but he is in a hurry to go back to Tifa. It is important to note that Barret is the one who pays Cloud, not Tifa, and there is no incentive for him to go back quickly as he’s already been paid for the earlier mission. In addition the player has the option of saying Tifa is his girlfriend to Aerith.

Aerith: So, what are you going to do now?”
Cloud: ..Is Sector 7 far from here? I want to go to Tifa’s bar. 
Aerith: Is Tifa…… a girl? 
Cloud: Yeah
Aerith: A girl… friend?”  

Regardless of what Tifa means to Cloud, her well being is important to him. Cloud sneaks out of Aerith’s house but Aerith then persists that she accompanies Cloud to Sector 7 despite Cloud telling her to go back home. Cloud and Aerith then sees Tifa being taken to the Don’s mansion. Aerith, knowing who the Don is, initiated the rescue mission. The plan of course, was one of the most hilarious moments in the game but Cloud agreed to it. His friendship with Tifa is the reason why he and Aerith go to Wall Market to find and save Tifa from Don Cameo and Cloud has an infamous cross-dressing scene where he has to wear a dress to get in. :) Enjoy this infamous dialogue:

Cloud: But, I just can’t let you go in alone… Oh, man…… First, we’ll need to find out if Tifa’s alright….
Aerith: You ARE worried about Tifa, aren’t you? Then come on, hurry!
Cloud: This is SOME underwear…. I’m supposed to wear this…? Well, if it’s to save Tifa… I guess there’s no way around.

Although the rest of Disc 1 has Aerith’s story be the focus, we will find some moments where Tifa becomes jealous of Aerith’s bond with Cloud as seen in this dialogue below:

Aerith "Cloud, are you there?"
Cloud "Aerith!? You safe?"
Aerith "Yeah, I'm all right."
(She swings her legs over the side of the cot.)
Aerith "I knew that Cloud would come for me."
Cloud "Hey, I'm your bodyguard, right?"
(She walks to the door of her cell.)
Aerith "The deal was for one date, right?"
(Tifa sits up.)
Tifa "............oh, I get it." ~FFVII script, Disk One

 Although it’s not the canon date, Tifa can date Cloud at Gold Saucer. The next important scene brings me to the Temple of the Ancients scene if Tifa is in the party. Fans of Tifa have stated that it was rude of Aerith to start flirting with Cloud in front of Tifa, but I didn't exactly see it as Aerith trying to be cruel to Tifa. For one, I believe that she was trying to cheer up Cait Sith by letting him tell his fortunes before he sacrificed himself. Although Cait Sith is known for reading erroneous fortunes, his predictions are not completely awry as many of them actually ring true. He's very much like the Polonius of FFVII, a foolish traitor with astonishingly insightful advice. Aside from telling him to give into the good will of others, to be careful of forgetfulness, and his lucky color, Cait also gives Cloud one of the most prophetic lines in the game:

"What you pursue will be yours. But you will lose something dear."

Which loosely translates into a victorious defeat over Sephiroth, but at the expense of Aerith' future alongside Cloud.

So then if Aerith is meant to die, why did Cait foresee a great future in their juncture?

"Looks good. You are perfect for each other!"
"Aerith' star and Cloud's star! They show a great future!"

By stars, he probably was referring to their astrological signs. In the Western Zodiac, Cloud is a Leo and Aerith is an Aquarius. These two are polar opposites and they easily bring to mind the old adage "opposites attract". Cait Sith enjoyed telling fortunes, and Aerith figured that it would be something nice to do for him. Cait Sith made that "Poor Tifa" comment, probably teasing Aerith (which would most likely explain why she turned around all embarrassed, because he was somewhat fronting her feelings off to Cloud). Nothing meant to be hurtful. Just a playful scene between friends.

The next important scene takes place in the Forgotten City where Tifa helps Cloud break Sephiroth's mind control trying to force him to kill Aerith. Now Aerith's murder finally causes Cloud to realize how much he loves her and that Cloud will never forget and would not forgive himself for until Aerith helps him with moving on past his guilt in Advent Children. Tifa gently caresses Aerith's hair and runs away in tears while Cloud totally breaks down and reveals his heart in a touching scene of his feelings of love for Aerith to Sephiroth. His pain, shock and guilt later cause him to almost quit his mission to defeat Sephiroth. And yet it was Cloud himself that said that he had to go on. Clearly that is easier said then done. When he came to remember his friendship and past with Zack (and of course his untimely death), that plus Aerith' death seemed to pile up on him. If there is anything about Cloud that is certain, it's that he remembers everything. Even though his memory was scrambled, even though his past was a mystery, he did remember what happened in Nibelheim and then remembered what happened to Zack. And when Aerith fell at the hands of Sephiroth, he most certainly wouldn't forget about it.

The next important scene takes place in the Lifestream event which itself is a complex and tangled web woven into the story of Final Fantasy VII. There are only two things within the Lifestream Event that Cloud rediscovers, which are his true role in the Nibelheim incident and the fact that he was never in SOLDIER. During the rest of the event, it is actually Cloud who is revealing things to Tifa. Cloud is led to believe that he was actually created by Hojo in a Nibelheim lab. So the whole purpose of the Lifestream event is to confirm Cloud's identity as having been born and raised in Nibelheim. What is meant by Cloud finding his “true self” during the Lifestream Event is finding out whether he is truly Cloud of Nibelheim or whether he is one of Hojo’s failed experiments. Tifa specifically asks Cloud to remember things having to do with her, since that's the only way she can verify whether his memories are true.

  

Tifa "That's it! What about some memory that has to do with me?"
 (She turns to the Cloud of the well.)
Tifa "I say something and you don't remember it......"
"But you say something, and I remember it, too... Then we'll know that's our memory......"

 

 In actuality, Cloud and Tifa barely knew one another as children, which is confirmed during the Lifestream event. Cloud only admits that he had a crush on Tifa in the past. He says nothing about loving her now. Tifa also says nothing to Cloud during the Lifestream event about loving him now. Tifa frankly tells Cloud that she didn't know him well at all:

Tifa "...that's right."
"We lived next to each other."
"But I really didn't know you that well."
  
Cloud also talks about how Tifa hung out with people other than him, and that he wanted to be part of her group of friends. However, he was never included:

(Young Cloud nods.)
Cloud "Tifa always used to be with this three-some."
 Tifa "...That's right."
(Young Cloud turns away.)
Cloud "I used to think... they were all stupid."
 (Tifa spins to face him.)
 Tifa "What?"
(He turns back to face Tifa.)
Cloud "You were all childish, laughing at every little stupid thing."
(She turns to look at her former self and friends, then back to Young Cloud.)
 Tifa "But we were children, back then."
(He turns away slowly.)
Cloud "...I know. I'm the one that was stupid."
"I really wanted to play with everyone, but I was never allowed into the group."

  

"......a sealed up secret...... wish......"
"Tender memories...... no one can ever know........."
 
 Cloud actually talks about several "secret" wishes that are painful or "tender" to him during the Lifestream Event. For example, Cloud tells Tifa about wanting to be part of her group of friends - he wished for that to happen, but he was always rejected. Therefore, that is a secret wish that's painful or "tender" to Cloud. In the second place, he also tells Tifa about her accident at the bridge. Cloud wishes that he'd been able to save her, and that he hadn't let her fall and get injured. He's never told anyone else about those things, so both are secret wishes. These memories are also painful or "tender" to him, since he felt awful about rejected from her group of friends as well as about letting her fall at the bridge. On top of that, Tifa's father accused Cloud of being responsible for the accident, which made him feel worse about it.


The fact that Cloud and Tifa didn't know one another well as children is confirmed when it's revealed in the FFVII Ultimania Omega that Tifa's memories of Cloud as a child are that of someone who was always getting into fights. The unfriendly personality which Cloud shows at the beginning of FFVII when he first joins Avalanche is actually based on Tifa's memories of him:
  
"Immediately prior to the start of the game, when Cloud's mind was shattered, he ran into Tifa and seemed to immediately return to "normal"; this was because the mimic abilities of the Jenova cells inside Cloud read her mind, seeing her memories of him, which were then combined with his own ideal vision of himself, fashioning a new personality for him. From: FFVII Ultimania Omega Translations at IGN, page 13
 
So the cold-hearted Cloud at the beginning of the game was actually based on Tifa's memories of him as a child. Tifa herself confirms this near the beginning of the game when she tells Cloud that he was always getting into fights as a child:
  
Tifa "When you were little you used to get into fights at the drop of a hat."
 

This shows that Cloud was blamed for letting Tifa fall at the bridge, and that Cloud thought Tifa hated him for it:
 
Cloud "That night I called Tifa out to the well..."
"I thought to myself Tifa would never come, that she hated me."

 

Cloud’s childhood relationship with Tifa were memories of rejection, guilt, embarrassment, and remorse, which we see clearly in the Lifestream Event. Tifa can not be blamed for this though because acts are judged by intention and she did not try to hurt Cloud.  In fact, Cloud's childhood crush wasn't even based on a childhood relationship with Tifa since they didn't know one another well. Tifa's presence during the Lifestream event was required since she was the only person who knew Cloud at that time. As a result, she was the only one who could confirm that Cloud was actually born and raised in Nibelheim rather than being created in a lab by Hojo. Thus Cloud and Tifa's friendship developed over Discs 1 and 2 and continues throughout the Compilation of Final Fantasy VII. I think Tifa was not deliberately mean to Cloud during their childhood, I think she was popular girl with many admirers and just did not notice Cloud. She is a tragic woman who is so human and many people relate to her. I am happy she finally became actually became friends with Cloud, she needs him and he needs her, they may not be lovers but have a beautiful friendship. This description captures Tifa's loving heart very nicely:


"After helping Cloud set up his delivery service, Tifa got involved with the displaced youth of Midgar and opened an orphanage. She keeps in close contact with Cloud and Barret and remains the steadying force she always was - or at least tried to be. Although she has a small role in this game, she remains as likable as ever and continues to show the traits that always made her such a great friend." ~Tifa's profile; Dirge of Cerberes strategy guide


The Highwind scene causes just before you fight Sephiroth in the Northern Crater. Cloud and Tifa were the only two with nobody to go home to or spend time with however there are two possible scenarios of the Highwind scene. One where Cloud is for warm and affectionate to Tifa and talks about their promise, hearing her in Lifestream and learns something from her in their Lifestream sequence. The other scenario is the exact opposite where Cloud is cold and standoffish to Tifa, implying it is the player's choice their affection for Tifa. I know both Tifa and Aerith well enough to know that they would be willing to sacrifice their own happiness for each other if it came down to Cloud choosing between them. They both come off as selfless to me. This scene does not give a clear answers to Cloud's affections or lack thereof for Tifa.
 

The end of the game was something very special, in my opinion. Cloud and company fight Sephiroth, and Cloud fights not only for his memories and the memories of the other party members, but the memory of Aerith as well. As stated before, she was his beloved, she was someone whom he would never forget. When everybody groups together, they attack Sephiroth, the real Sephiroth, in a climatic battle that would decide the fate of the world (as cliche and dramatic as that may sound). And they succeed. Sephiroth is defeated by everyone in the party... except for Cloud.

 Kingdom Hearts and Final Fantasy VII are tied together in the fact that Sephiroth is Cloud's darkness. He is the dark side of Cloud, he is something Cloud cannot forget or perhaps escape. Sephiroth is a deep, dark memory in Cloud's subconsciousness that has haunted him for years, ever since he was that Shinra soldier that returned home to Nibelheim. The final battle of the game, the ultimate battle in Final Fantasy VII is between Cloud and Sephiroth. Cloud seems to pass into a dreamlike state, where he is pulled through time, space, into nothing but absolute darkness where Sephiroth waits. On his way there, Aerith's theme plays. That seems to be pure symbolism to me. Aerith's theme played when she had died, it played when the Holy Materia fell into the water and when her body was buried in the lake. Her death seemed to be the last straw for Cloud. Sephiroth had taken everything from him: his home, his friend, his mother, and almost his sanity. When Sephiroth took Aerith from Cloud, that seemed to be what triggered him off. He knew he had to finish it once and for all, he knew he had to defeat Sephiroth and make him pay for all that he had taken from Cloud. Aerith's Theme plays for two reasons: one, possibly to symbolize the crisis that was going on. The world was still on the brink of collapse, and that was something everyone, even Aerith herself, did not want to happen. Two, was to remind Cloud of not only the fate of the world, but also what had happened to Aerith. To remind him that she was gone, just like Zack, just like his home, just like his mother. And that was all Cloud needed to remember, all he needed to have with him. And when he sees Sephiroth in the darkness, his eyes are focused and he is ready to fight.

Cloud battles Sephiroth, in the darkest part of his subconsciousness. And when Sephiroth is defeated, that was when Cloud sees the light. The Lifestream wraps around him, and light begins to shine in the darkness. That is when Cloud looks up and sees Aerith's hand reaching out to him. He smiles and reaches for the light, reaches for Aerith's hand.

I like to think of it as Aerith guiding him into the light. She was leading him out of his darkness, and once he made it out, Aerith's hand vanishes and Tifa is there, reaching out for him. Aerith loves Cloud but she knows that he has friends waiting for him in the real world, friends that love him and would be deeply saddened if he was to leave them. Aerith is not a selfish character, she wouldn't want Cloud to stay with her if it meant hurting his friends. The way I see it is that Cloud did not necessarily "choose" life over death. I think that was the last thing on his mind. What he did was choose light over darkness. Sephiroth was gone now, so there was no need to linger there. The light was coming back into his heart, and Aerith hand was reaching out for him. She might have been asking him to come with her, not into the Lifestream, but back to life itself. That is why Tifa's hand appears when Cloud enters the light and wakes up from unconsciousness. That is why Aerith controls Holy and saves the world.


Tifa isn't a very selfish person, that is why she ultimately sacrifices her happiness for Cloud as shown when she accepts Cloud's decision to meet Aerith in the Promised Land.


Cloud and Tifa had a very strong friendship. They gave so much to each other, they showed each other so many things and went out of their way to help one another. Although it wasn't meant for them to be together, although calling them lovers would be too farfetched, what they had was real. What they had was good enough.