Adric is a fictional character played by Matthew Waterhouse in the original 1963-1989 run of the long-running TV series Doctor Who. He is a young teen from the planet Alzarius in E-Space, serving as a companion to the fourth and fifth regenerations of the Doctor.
He first appears in the season 18th serial “Full Circle” (1980), and is seen trying to escape the misfortune plaguing his community, and accidentally stumbles and takes refuge in the TARDIS. He stows away with the Doctor, Romana, and K-9, until he is found in the following episode “State of Decay” and is then made a full-time companion by the Doctor.
Adric is a brilliant mathematician and a bit cocky, as he knows the full capacity of his intelligence. This leads him to carry himself with an air of superiority and arrogance that is shown to get him into trouble. He seeks the approval and validation of the Doctor and those he meets while on his travels but feels resentment when the Doctor sidelines him, as he feels that he could better handle situations due to his intelligence. This aspect of his personality is both a strength and a source of conflict, as it strains his relationship with the Doctor and other companions due to his arrogance and desire to prove himself. Frequently putting him at odds with other companions, mainly Nyssa and Tegan.
He unfortunately meets his end in the series in season 19 episode 21 “Earthshock” (1982), when he attempts to stop a Cyberman and heroically sacrifices himself in the process to save the Doctor and his companions. He dies in a spaceship crash headed toward prehistoric Earth, still holding on to the hope that his intelligence will save his life. It is later revealed that the spaceship was a fixed point in time of the asteroid that killed off the dinosaurs.
Although that is his last appearance in the TV show, his character is further explored in other multi-media materials, including the Big Finish Production audio dramas, novels, and comics, helping him become one of the most well-rounded characters in the expanded Who universe by allowing him to live in different timelines and universes.
In the novels The Boy That Time Forgot and The Star Men, his legacy and character get a more nuanced development, adding depth to his arc. Other novels such as Cold Fusion and Divided Loyalties expand more on his backstory pre-TARDIS, hinting at plot lines mentioned in the series.
One of the biggest explorations into Adric’s character is his sexuality, most notably, his bisexuality. It is first subtly introduced in the novel Divided Loyalties by Gary Russell. In this, the story suggests that Adric is attracted to both male and female characters. It is not until the audio drama “A Full Life” that his bisexuality is explicitly mentioned, giving us a more detailed explanation of his relationships. It is revealed that in “A Full Life”, he gets to live, eventually marrying and having children. After his wife Asun passes away, he marries Reebac, a Veridian man, confirming his bisexuality once and for all.