I don't know how Bruce went downhill in this AU--if he started out that way or pre-film, or if Alfred chose to remain by his side after this fall (doubtful), but the point is that the Bat is an unpredictably powerful, scary and influential figure in Gotham's underworld and beyond--though most 'beyond' can't decide if he's a myth or real, much like canon--whom saves lives or takes them depending on however his mind's working at that particular moment. What's the deal with his Robin (Dick Grayson--Zack Snyder confirmed it) who died? IDK. There's a lot of legroom for you to work with.

But *this* is the point: MoS happens, and he decides his mind is working on hunting down the alien god responsible for the destruction of the Wayne Enterprises building in Metropolis. He's the one getting to the kryptonite first, Lex is aggravated but not backing down from trying to kill the Superman himself. He doesn't connect that Bruce doesn't necessarily want to *kill* the Kryptonian.

Dubcon, noncon, dominance, mindgames. Scouring for anything about Supes' daily life, snooping his secret identity when he finds it out eventually, acting like he's fascinated by everything Clark does and surprised when he behaves just normally. But also not really acting worshipful the whole time -- he's analyzing everything like a xenobiologist and someone readying for murder all the same.

I hope this isn't too incoherently rambly.