The Ending Of The Flash Explained

When we meet the alternate universe's version of Batman, we find him with his crimefighting career already over, living alone in a dusty, rundown version of Wayne Manor, with nothing to do all day but drink and grow his beard. Eventually, he explains that it turned out this way because he did his job a little too well. Gotham City is no longer crime-ridden, they don't need Batman, and as a result, Bruce Wayne is a lost man, someone with no real sense of purpose now that his singular mission is seemingly complete.

Meeting the two Barrys, and eventually Supergirl, helps Batman see a new path forward for himself, so much so that he eagerly shaves, straps the suit back on, and goes into battle alongside his new friends. It's a fight he clearly relishes, in part because he's never had the opportunity to fight alongside metahumans before, but mostly because he has a purpose again and it feels good to get back out there.

Eventually, as the climactic battle rages and the Barrys' time-traveling proves useless in changing the outcome, it's clear that Batman is meant to die trying to save Earth from General Zod. It's tragic, but not for Bruce Wayne himself. For him, it's a good way to go out — doing something to help others, fighting evil for as long as he can, as hard as he can. It proves the kind of hero he is, the kind of hero he always was.