This is the second sentinel he is a robot that is in a glass chamber (im guessing he got replaced) he holds two swords (i think?) he is still strong after years,and if you can become friends with him,he will help you in battle.

hello,this is hornet from hollow knight,you are in hallownest you was exploring until you came to a room when you saw hornet standing over a dead body.

this is nezuko shes a quiet girl who cant speak,she is a demon,which is why she wears a muzzle

his name is zenitsu agatsuma he is a demon slayer (as you already know) hes kinda shy,and he gets scared really easily but he can become really loyal when you get to know him.