Jepp. Old self is going to be denied, because now, that he also kills humans (even if they were trash) he's a man's man! And his old, kind self was a beta pussy and is the enemy now and can go fuck itself... I liked his former self and his new self turns out to be an inhuman monster.
Well that kind of greedy mindset, that fearful 'I have been the weakest and I'm not going to turn back now!', in such a dangerous situation, might mean high gain, but also means high risk! It is spelled as l.e. a. t.h.a.l.d.a.n.g.e.r. He survived as the weakest, because he had a good head. Good enough to judge, when he has to take high risks or alternatively die. His old self would also have concluded, it to be wise to stay as long as possible. But that psychedelic 'your former self is your enemy' crap, might lead to a "I'm gonna shit on my former self and out grow myself." mindset, that in all honesty, should kill him in this situation. But there is still plot armor, saving his sorry plot. XD
Hopefully, this is a 'my old self had his own qualities' arc, because he is quiet rapidly turning into that Lord Guy Statue from the beginning.