Since I had to dig up several stuff, cuz apparently a ghost cant be just taken like the general one the definition does by google, I will go over several things
1) Jinpachi is said to be have powers of
a revengeful ghost, which is what possesses him in the game, which even last year Harada talked in details, once again, by stating its
a vengeful spirit, Devil Jin in his tekken 5 ending absorbs that and adds it to himself, which in the profile its accepted as soul absorbtion
2) Jun had to fight the
spirit/ghost of Devil so it didnt get Jin soul, whom was in her belly at the time, Kazuya at this point in time was dead, 15 years later when the events of the next game kickstarted, Devil is once again showing up,
taking over Jin like he wanted back then, Kazuya in his Tekken 4 ending absorbs that part of him, which in the profile its accepted as soul absorbtion as well, you literally
see visually its incorporeal
3) Azazel was just
a spirit, which needed
a physical body via Jin and Kazuya, even after Jin kills him, his
spirit/ghost still existed, which Zafina had to seal it in her body, which in
T7 and
T8 Azazel makes her arm change into his, taking possession of her, Kazuya even pulls
his spirit/ghost out of her
4) Claudio, a literal exorcist uses his power to force the spirit/ghost that
possesses a child
So not only ghosts/spirits exist in the series, especially of dead people, but also either they show possessing others or show up by themselves, meaning they have no physical body and I pointed earlier last page, Kazumi when she is beaten by the player character, she fades as light particles or whatever you wanna call that, she isnt a physical being, ghosts in the series are treated as non corporeal entities, exactly like your average ghost does by the dictionary "the
spirit of a
dead person"
So those of you beating around the bush about semantics of a what a ghost nature is based on no standard or note of it existing on the wiki should drop it already
