Oh boy I'm so glad you asked. Various media have differing interpretations of corpse puppets, but the general idea is that it's an animated corpse, frankenstein, or other form of corporeal undead that obeys a cultivator's directions. I was principally inspired by the Black Fiend School arc of Record of a Mortal's Journey to Immortality (chs. ~279-330) in re the ascending-in-Realm thing; the main antagonist of that arc had several corpse-puppets that were possessed by spiritual clones of him and were capable of independently cultivating.
I am planning to include at least one "classical" cultivation system in the setting chapter in v0.3, which is like 80% of the way to being done rn I'd say, hopefully should be ready by the end of the month.