Really interesting thought. If that's the case then Law really is one manipulative motherf## , even more than Jesse. After all, Jesse did say once that the name Brown suits him more. But I really do think that it was Jesse who said those lines. My reason is because I don't think Law has ever thought of Jesse as a puppy. All this time we've been reading things from Law's POV and I think the author wanted to end it with Jesse's thoughts.
but if you think about it thats what law would say judging by his previous POV
I'm not so sure that's Law's thoughts at the end. If you look earlier in the manwha, Jesse refers to Law in this way. So it would make sense for him to refer to him again like that at the end.
From this chapter i can say that law finally got what he wanted. I mean everyone's thinking that the Last monolog is of jess but in my opinion it sounds more like law. I maybe totally off but the little smirk he had in the end kind of tells me that it's him who is saying those lines. His calm look and jess's panicked look makes it feel like he finally got control over jess. This story was confusing but all i wanted was more sexy and yandere moments (￣∇￣"). It was mindfuckin story (〜￣△￣)〜