Ripa 'Moramee is the arbiter from halo wars.
Ripa was revived by Odst grievous in an ectoplasmic accident. Ripa learned of the destruction of the ark, and, in his rage, slew Grievous's parents. The two have been worst enimies ever since.
Encounter on HothEdit
ODST Grievous isn't the only Coalition member Ripa fought. When Squad 'Explorer' arrived on Hoth, they discovered that Ripa's Hideout was there. The group fought the undead Sangheili in the ruins of Echo Base. He was forced to retreat when 'Holly' arrived in one of Growvole's Battle Droids (after hacking her way into its AI Matrix), Growvole being the Base's former tenant.
The ectoplasmic energy Odst grievous put in him revives him whenever he is killed. Other than that, he has no powers to speak of.