Meeting Amanda Waller
Dexter and Admiral Olsen meet ARGUS leader Amanda Waller, who presents to them her idea of Task Force X - a team of expendable, obedient individuals with exceptional powers or skills, who would be there to defend the world if an opponent of Superman's caliber ever emerges to threaten it. Amanda then presents her candidates to an ambivalent Dexter and Olsen: the lethally formidable marksman Deadshot; the notorious rope assassin Slipknot; the prolific Australian bank robber Captain Boomerang; the formidable psychopath Harley Quinn; the mighty metahuman Killer Croc; the exceptionally powerful pyrokinetic metahuman El Diablo; and finally Enchantress - the most powerful metahuman that Amanda Waller had ever come across. Amanda also adds that US Colonel Rick Flag would join the team as its leader, along with his extremely formidable samurai bodyguard Katana.
Ultimately, however, Admiral Olsen objects to the proposition, appalled at the idea of Amanda entrusting homeland security to assassins, psychopaths and crocodiles. Waller, however, remains adamant, and intends to present her idea at the Pentagon, and Dexter is more supportive of her idea.
Presenting Amanda's idea
- "What if Superman had decided to fly down, rip off the roof of the White House, and grab the President right out of the Oval Office? Who would have stopped him?"
- ―Dexter Tolliver[src]
Dexter ultimately accompanied Amanda to the Pentagon, where her Task Force X idea was officially presented, along with a visual demonstration of the powers of the most powerful intended recruit into the task force - June Moone, who swiftly transformed into the fearsome Enchantress.
Enchantress' escape and Task Force deployment
Dexter and Amanda's fears ultimately prove to be valid, as several days later June transforms into the Enchantress during her sleep, subsequently escaping and opening the vial containing the spirit of her brother Incubus. Enchantress then takes to Midway City and incapacitates a man in the subway, with Incubus forcing the unwilling human to host him.
As the two mystical Meta Humans fully build up their powers, they become the incredibly powerful threat that Amanda had foreseen, as while Enchantress and Incubus would also, like Aquaman, Flash and Cyborg, be inspired by Superman to come out into the light, the intentions of this duo are far less benevolent - recalling how they were once worshiped as gods by ancient humans millennia ago, both of them resolve to conquer Earth and subjugate its inhabitants to their will. Thus, the implementation of Amanda Waller's Task Force X that becomes necessary, with Dexter's approval.
Dexter was Task Force X's largest government supporter, present during all of its pitches and deployment. He showed a genuine loyalty to his country, authorizing the program as he felt it was in America's best interests. He appears to be a very good listener and remains calm under crisis; he demonstrated the most control out of all the government officials during Enchantress' attack. Dexter also remained very informal despite his position, introducing Waller's idea of Task Force X while lounging in his chair.
- In DC Comics, Derek Tolliver is the liaison between the US Government and the Suicide Squad. He later turns on the team and attempts to frame Amanda Waller, but he is killed by Rick Flag.
- He briefly wears a brown trenchant in Suicide Squad as an homage to his appearance in the comics.