Batman stomps. And I am not trolling I am serious. Not only does batman have the mental capacity and execution that is needed to use ryu at a high level. But he would most likely stomp due to the fact that Dan is one of the worst characters in the game. So Thanos would automatically be at a disadvantage. I would know this because I play ssf4 competitively. Supposedly Dan is going to get buffed in the next iteration of street fighter coming up next year.
Let me get this straight, you gave Batman (the man that has a spectacular memorization capability, incredible intelligence level, nearly unsurpassed timing and execution) one of the best characters in all of Street Fighter history (Ryu) and you gave Thanos one of the least impressive characters in the game (Dan). What were you thinking?
Well to be fair ryu isn't great in ssf4 he is mid tier at best and has alot of bad matchups , but he is still a far better character than Dan. But Dan is still a very viable character and can win against great characters depending on if the player is skilled enough.
Thanos gets upset and accidentally breaks his controller and throws the TV through the window in a fit of rage.
Batman: "This is why we can't have nice things!"