History
The Trinarians attempted to colonize Ego, the Living Planet, and in retribution, he threw their homeworld into a black hole.
This upset two Celestials by the names of Gammenon the Gatherer and Jemiah the Analyzer, who had been performing genetic experiments on the Trinarians for Eons, and Ego ruined them. Ego was eventually brought to justice and killed, but the Trinarians were already extinct.[1]