Anybody ever dealt with a previously domesticated cat becoming a bully to the local ferals?

There's a big, previously domesticated cat (he had a collar that wore down and fell off) that started showing up where I feed some ferals and he immediately took over the territory and became a menace to the community.

I've never seen a cat this aggressive in my life. He's super sweet to people but he will immediately chase down and beat the shit out of any cat that comes near "his" territory. Just bolts off like a hunting dog. He's strong as hell too so he mostly has fun doing it.

I've exhausted all possible efforts to find any owner that could be looking for him and nothing has happened. I really do not have room to take him in, nor do I want him with my other cats. I have considered contacting a local no-kill shelter. My only concerns are that he isn't "my" cat and still has a visible collar mark.

Would they put him up for adoption with the "potential" that he's someone's pet even though I've searched for owners for over a month? Has anybody dealt with a similar thing?