Renton's father was a military researcher considered a hero by the military. Original author of the Ageha Plan, which he then sought to have buried as being far too destructive to ever be implemented. His team was conducting experiments involving the Seven Swell phenomenon. It's revealed in a conversation between Eureka and Renton that Adroc vanished during an experiment on the Amita Drive. He prevented the full destructive force of the experiment from being unleashed by removing the Compac/Amita Drive from its socket in the Nirvash, interrupting the transdimension rifting that would have led to the planet's destruction, but in the process was himself taken bodily into the rift it created; nothing of him or his uniform remained, save the Compac/Amita Drive. He was later declared dead, and a massive monument, now largely unvisited by an uninterested public, was erected in his home town of Bellforest.
Later, it's revealed that his state of being was transferred to the Scub Coral along with other human beings, some of whom in normal reality were apparently suffering from the seeming catatonia caused by Despair Sickness. These individuals' consciousness apparently exist in a non-temporal state. They were staying in this form by their own will to communicate with and to attempt to understand the true nature of the Scub Coral. When Renton finally met with his father again, there was no hatred; Renton held his hand and was glad to see him without any animosity from his past feelings.
Adroc has no voice actor throughout the series. The only scenes in which he appears are either narrated flashbacks or non-speaking roles.