The Riddler (Batman: Assault on Arkham)

Driven by a compulsive hunger for attention and desire to prove his intellect to the world, Edward Nashton (also known by his alias Nigma) fashioned himself into the iconic villain known simply as The Riddler.

Batman: Assault on Arkham
At some point, he managed to be recruited into the Suicide Squad, which resulted in him learning about the explosives as well as how to deactivate them. The Riddler had been involved in The Joker's theft of a dirty bomb with enough power to wipe out more than half of Gotham should it go off. Sometime afterwards, he managed to steal data relating to the Suicide Squad. He then entered a communication with Director Amanda Waller where he attempted to prove his superiority by giving her riddles for her to solve. However, unbeknownst to him, Waller had deliberately contacted him in order to stall him long enough to get a pinpoint on the location of his hideout in the Gotham docks and have him taken out in a black ops operation by A.R.G.U.S.. However, he was rescued by Batman from his would-be assassins, and then captured and interrogated by Batman himself as he tried to escape in the confusion, due to Batman trying to track down Joker's dirty bomb. However, the Riddler doesn't know where it was located, so he was then sent to Arkham Asylum. The failure of the black ops mission resulted in Waller sending in the Suicide Squad to recover data from the Riddler and presumably assassinate him.

He eventually encountered the Suicide Squad, who had been dispatched with recovering the data of the Suicide Squad members, although he managed to help them with getting rid of their explosive bombs by shorting them out via electrotherapy. Unfortunately, he wasn't able to save King Shark from his explosive because his skin proved to be too tough to actually short out the bomb encased inside him. He managed to escape into the night after the Joker released the various Arkham inmates, taking advantage of the confusion.