Geistalt
Combative abilities only (just to make it clear I'm not talking about authority in other areas).
Human: Darth Sidious
Sith: Lord Scourge / Darth Soverus
Miraluka: Visas Marr
Yoda's Species: Oteg
Chiss: Dazh Ranos (behind Sev'rance Tann)
Mirialan: Somminick Timmns (behind Luminara)
Zabrak: Gethzerion
Human: Darth Sidious
Sith: Lord Scourge / Darth Soverus
Miraluka: Visas Marr
Yoda's Species: Oteg
Chiss: Dazh Ranos (behind Sev'rance Tann)
Mirialan: Somminick Timmns (behind Luminara)
Zabrak: Gethzerion