As the title states, not a theory. Marvel and DC crossover idea.

Bruce Wayne and Matt Murdock (Batman and Daredevil respectively) became buddies after Nelson and Murdock helped out a Wayne Industries building that was being put up in Hells Kitchen. Wayne and Murdock quickly bonded despite Foggy claiming Bruce had "a really weird creepy vibe to him"

Bruce finds out Matt is Daredevil  (Worlds Greatest Detective)

Matt finds out Bruce is Batman (heightened senses; listened to heartbeat etc)

They team up to fight some members of the mob....

Before Punisher appears and kills everyone.

Bats and Devil Boy spend an hour lecturing Punisher on not killing.

Punisher kills two more people......

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But not them. Some Irish guys.

Another hour lecture on not killing people.

The friendship between Bats and Murdock ended when Electra and Thalia Al Ghoul teamed up; Electra seduced Wayne and Thalia took Murdock.

Yep. It ended because of women

XD

(Don't take any of this seriously, I'm kind of tired...I should probably sleep)