HG's special ability can be kinda anything.
Chariot's special ability isn't exactly related to the stand itself. Like Body swapping doesn't exactly tie into Knights/Swords/Impeccable Speed.
Same as for GE that can create life. It's ability in GER doesn't come in ties with the appearence/main ability of normal GE.
HG's special ability could be idk... be anything? Think Green. Like. Emit green, deadly gases.