@Serapheid
weren't the collar kinda explained before...? or maybe I'm confusing the detail with another story...
but him being an isekai'ed person or well, the established knowledge in that world that slavery or mind control magic exist, couldn't he just theorized and try it out and destroy a collar to see what happens?
well, we'll just have to wait and see what happens after. but I still think in that situation it's smart to take the chance (if you get one) to destroy a suspicious collar on a slaved animal. at worst, they die, at best, they turn feral or on their slaver...