In Season 2 of Invincible, after the newest member of the Coalition of Planets, Aikreon, was immediately attacked by the Viltrum Empire, the leader of the Coalition, Thaedus, tasked Allen the Alien with rooting out a possible mole within their ranks. But before Allen could even begin his investigation, he was ambushed by three Viltrumites.
They had questioned him about Mark Grayson and whether he was truly Nolan's son, something they shouldn't have known about. When he declined to tell them anything, they mortally wounded him. Thankfully, Allen survived his near-death experience and became even stronger than Invincible, leading him and Thaedus to be certain that they had a spy among them.
There were plenty who could have leaked this information about Nolan's son to the Empire, since Allen reported this news to every council member of the Coalition, many of whom were skeptical of recruiting Mark Grayson in the first place. Any one of them could have gotten cold feet and made a deal with the Viltrumites to spare them and their people from the same fate as Aikreon.
Concern over this potential mole returned in Season 4, when Allen finally brought Nolan to the Coalition of Planets to meet Thaedus, with Allen's girlfriend and superior, Telia, taking extra precautions against any further leaks. However, the mole inside the Coalition has been in plain sight all this time, with all the data at his fingertips to leak to the Viltrum Empire.
Who the Spy-Mole In the Coalition of Planets Is In Invincible Comics, Explained
As Allen and Nolan entered the Coalition headquarters, passing the Data Twins, aliens who oversaw the data records of all Coalition agents, the two immediately suspected that their new mustached visitor was a Viltrumite.
While the first twin was merely cautious, the camera suspiciously lingered on the larger twin as he contemplated another Viltrumite joining the cause against the Empire. Unless this is a red herring, then it's clearly foreshadowing Data Twin II as the suspected spy inside the Coalition, like he is in the comics.
This betrayal is revealed in the final pages of Invincible #73, showing that Data Twin II has been reporting directly to the Emperor of the Viltrumites, Thragg, for years. His last order from the Emperor would be for him to shut down the defenses of the Coalition headquarters, leaving them wide open to Thragg and his army.
The Empire was almost successful in destroying the Coalition once and for all, with the situation becoming hopeless. Before they were all killed in the overwhelming attack, Nolan, Mark, and Oliver returned to help in the fight after Invincible killed Conquest once and for all, driving the Viltrumites back to their home planet to prepare for a counterattack. After the Viltrumites retreated, the first twin was the one to finally out his sibling as the traitor.
Unfortunately, even comic readers never learn much more about Data Twin II or why and how he became a mole for the Viltrum Empire. He likely betrayed them out of fear against the Empire's overwhelming power, as he told them all once his role as the mole was revealed, "You've got no hope of winning this war."
Considering how much this animated series has expanded on plot points and characters, even reviving a scrapped Damien Darkblood story from the comics, it wouldn't be a surprise if we learn more about Data Twin II and his motives for betraying the Coalition by the end of this season.
