vash was at the academy with him for two years when he was 14-16! he was a major little shit, did not want to be there, didn't present with any major abilities until more recently, set fire to a lot of things, got into fights, was the class clown and rebel, most instructor's least favourite student, and eventually got into so much shit with no pay off (aka abilities) that he ended up expelled and stealing an instructor's ship and ended up (momentarily) arrested til that instructor bailed him out. deep breath so depending on what carsin was like at the academy, vash could've either been a friend or a thorn in his side!