Citrine

Citrine is a transformation gem that once lived in Enthis. He is considered to be the oldest living Sage, but no one is quite sure of how old he really is. 

He was one of the first Sages in the Enthis area, back when it was still made up of small separate villages. He was friends with Zircon and Sage Turquoise in Enthis and later befriended Titanite and Kyanite when they became Sages. As one of the oldest practicing Sages, he once held a high position of authority in the Council. It is said that he was once a much more firm and authoritative person during his time in the Council, but has become quite lax over the cycles. In the cycles leading up to the Council's eventual disbandment, he served more as an advisor and counselor to individual Sages than a leader of the entire group. Shortly after Sapphire became paranoid of transformation gems, Citrine disappeared seemingly overnight, and only his closest allies know his whereabouts. 

His unique ability is that his flesh is made of a deadly poison. Though completely harmless to touch, consuming any amount of it is said to kill anything within three days. Though full of wisdom about many things in the world, he has a very dark sense of humor and sometimes makes poison from his flesh for fun.