When Slade put his plans of conquering Jump City with the help of his new apprentice, Terra, in motion, he had her break the three monstrous villains Cinderblock, Plasmus, and Overload out of jail to split up the Titans and lure them into three separate ambushes.
The plan succeeded in its initial facet, but the Titans survived Terra's attempt on their lives and prepared to take her down. Striking from ambush, they terrified her so much that Slade sent in Cinderblock, Plasmus, and Overload to assist her. Using an unknown technology, he fused the three with each other, creating Ternion. However, Ternion was quickly taken down by a limpet charge placed on its back by Robin and, while incapacitated, the three 'component' villains were separated again, allowing them to go their own ways.
Teen Titans Video Game
Plasmus, Overload, and Cinderblock teamed up together to form Ternion again. This time, Overload is running low on energy, so he drains energy from a power plant to recharge, while Plasmus and Cinderblock stand by to guard him. The Teen Titans fight Plasmus' clones and Cinderblock in a minute before Overload finishes recharging and merges himself with Plasmus and Cinderblock to become Ternion. The Titans' first priority before fighting Ternion was to take out the electric force field protecting him. After they defeat Ternion, he disappears from the video game they were trapped in.
Powers and Abilities
Ternion combined to a certain (and as yet undefined extend) the abilities of Plasmus, Overload, and Cinderblock in one body. Manifested abilities of this crucible shape included:
Superhuman strength and high resilience to physical and energy attacks (Cinderblock)
Forming of extra pseudopods (Plasmus)
Channeling electricity through those pseudopods (Overload)