That old man who at the very beginning was stuck in the refinement of QI realm, and entered the blood trial to get herbs, is actually the most powerful being (at that time). He was faking his level, but in fact he is above the nascent soul which is the "Deity Transformation", and when the war happens he simply leaves because he doesn't care about anyone, he just wanted the herbs.
No same like the novel / Donghua no hidden identityMortal to Immortal
just got confused with these levels 1 to 6... I need to reread the beginning of the novel because I don't remember this numbering. I'm even afraid they even changed the names in the cultivation path that I'm already used to.