How to collect essence? (Hollow Knight)

Did you kill everyone? The fact is that in addition to the bosses of dreams (xero, markot, elder hu, blind, hump, etc.) there are complicated versions of ordinary bosses: a broken champion (horn knight), a lost fellow (broken vessel), a murderer (master of souls) , white protector (dung protector). They can be found at or near the place of death. They must be warmed with the nail of dreams, and defeated. They are complex, but give a lot of substance. (The white protector can be found by breaking the floor under the lever that you pumped out the acid with after defeating the dung protector; the lost brother and murderer will be in the place of his death)