Final Fantasy VII, Angeal/Cloud, age difference 1/2
Angeal found it odd and a little sad that sometimes Cloud seemed older than Zack. It wasn't any one thing he could point to; perhaps the fact that it was Cloud who'd restrain some of Zack's wilder schemes, the way he was far more serious about Zack's training than Zack was. Angeal was used to his student turning up for a sparring session rushed and out of breath, with an apologetic look and a ducked head that said he knew he deserved the lecture he was about to receive. But if he turned up on time, and looking like maybe he'd already had a lecture or two, Angeal knew that he'd been with Cloud.
After awhile, he realised it was something else. Zack was irredeemably positive; he saw the best in everything and everyone, and being shown otherwise didn't discourage him. He'd be disappointed, but still optimistic overall. But Cloud was different. While Zack brought out the playful side in the younger boy, the part that would let itself be dragged into pranks and hi-jinks, Angeal could sometimes see something darker in his eyes, something wary and watchful. Although he might be two years Zack's junior, Cloud already knew that the world was not a kind or happy place, and probably had a better idea of just what kind of company ShinRa was than Zack did, for all that Zack was rising through the ranks of SOLDIER.
It wasn't just that Cloud was good for Zack, Angeal decided, but Zack was good for Cloud, too. Zack teased and cajoled and coaxed him into jokes and laughter. When he was around Zack, Cloud acted more like the teenager that he was. So Angeal encouraged the friendship as much as possible, and relied on the fact that while Zack might now have a partner in crime, Cloud wouldn't let him get into too much trouble.
Perhaps that was why he was completely unprepared for it when Cloud set out to seduce him. He'd had a determined look in his eye when they began, and something that suggested he was just waiting for rejection, and that had been Angeal's undoing. When Angeal tried to voice an objection, Cloud flinched, and all he'd wanted to do was soothe that hurt look away.
He'd ended up doing far more than that.
It was only afterwards that Angeal started putting things together. He'd been more than a little guilt-stricken for bedding someone so young – his student's best friend, at that – but Cloud had been happy, a little relieved. Angeal had received a shy smile rather than recriminations, a brief but affectionate touch, and something that might have been the beginning of confidence in Cloud's eyes.
Cloud knew how close Zack and Angeal were: far closer than the usual mentor-student relationship, if not what gossip sometimes made of them. He had probably heard things about Angeal from Zack, because Angeal knew full well that Zack talked endlessly about the people he liked, and what he liked about them. But just as Angeal had pegged Cloud as Zack's best friend, Cloud had picked Angeal as being the other person most important to Zack, and had sought to assure himself of a place in their relationship. It made Angeal feel positively murderous to think of who might have taught Cloud to think of sex as currency, because he had no doubt that that was precisely what it was. Cloud was too young to be thinking that way.