In Gotham City, there's no one you can trust. But for most of Gotham Season 1, Fish Mooney's associate Butch Gilzean has been the single exception to that rule. Still, as much as he's proven his loyalty, even murdering one of his adolescent friends because he didn't support Fish's coup, could Butch betray Fish Mooney? If he does, he'd really have given everything in order to get ahead. He has no closer friend, no closer confidant, and he spends literally every second of his screentime either listening to Fish describe her plans or acting as her muscle. And if he has betrayed her, than he'll be one huuuuuge blind spot in Fish's plan — how could she not have vetted her BFF better?
If you think about it, Butch is in the position that we expected Penguin would have taken back in the first few episodes. He's Fish's sidekick and lapdog, quietly biding his time and assisting her, maybe hoping that he can eventually take over. But Gotham has sped up the timeline considerably — Carmine Falcone, one of Batman's biggest foes, already seems on the edge of being destroyed, and the actual Penguin has basically inherited Maroni's entire empire, after only working with the mob boss for a couple of episodes.
But Butch could be a fraud. He's seemed extraordinarily loyal so far, but who knows. In "What the Little Bird Told Him," didn't it seem like he was pushing that congratulatory drink a little too hard? You'd think a seasoned mobster wouldn't celebrate before truly eliminating the competition. And Butch sure looked disappointed when Fish didn't even touch the glass. It totally could have been poisoned, and if it was, my heart is broken. I have been friendshipping Butch and Fish since the very first episode of Gotham. You don't see a female boss with a loyal male lackey very often, in comic books or television series.
Butch could be working for Falcone, as the deepest undercover agent in history, even deeper undercover than Penguin, who changes sides at least once per episode. But if Butch is working for Falcone, I don't see why he would have been worried about the Liza'napping for even a second. He could be working for Maroni, because a Fish takeover would mean that the second most powerful person running the Falcone family would be in his pocket, but then I don't see why Butch would help the enemy.
Basically, if Butch is betraying Fish, he's got to be in it for himself, right? The only motivation that would make sense is if he wants to ride her coattails to the top and then kill her. And while it would make for a dramatic conclusion to the season, I have to say that it would ultimately be disappointing, because the Fish/Butch relationship is one of my favorites on Gotham.