Sothisq
Very well, the story is developing slowly, the characters are reasonably realistic, the interaction between the world, the MC and other people is ok. Keep developing like this, slowly and steadily, the golden fingers of the story are already exaggerated, so for the story not to lose its excitement, care must be taken. I know it's a dangerous world, but that's what captivates readers, the adventure, the effort, personal overcoming, growth and maturity, both of the mc and the other characters.
The killing curse doesn't kill the soul it separates it from the body if it killed the soul Dumbledore wouldn't be in the afterlife or on the way there, besides I highly doubt it would work on creatures like basilisk, dragon and many others if it were so easy to kill these wizard creatures wouldn't be afraid of them, apart from the fact that the curse is slow, I doubt it would surpass the speed of a low-class demon and many other beings, including humans from DXD, apart from the fact that a simple armor would be enough to protect against the curse.
U author can u post some pictures for the mc ? Also please don't make the mc a hero nor a villain Also hope u can add these girls to the mc harem ( supergirl + power girl + wonder woman + Donna troy + artemis of bana-mighdall + raven + starfire + star sapphire + divine dc + circe + zatanna + ravager + black canary + blackfire + mera + hawkgirl + hawkwoman + hippolyta + antiope + Jessica cruz + superwoman + death of the Endless + mother night + pralaya + hecta )