Grag, an intelligent robot forged by scientists Roger Newton and Simon Wright in a lunar laboratory during artificial life experiments, stands seven feet tall with a durable metal frame built for heavy labor and combat. While his cognitive abilities are more limited than those of his android counterpart Otho, he demonstrates steadfast loyalty and a fierce protective instinct toward his allies.

After Victor Corvo murders Roger and Elaine Newton, Grag joins the retaliation, eliminating Corvo under Simon’s command. This act positions him as a primary guardian of their orphaned son, Curtis Newton, alongside Simon’s disembodied brain and Otho. Though Grag assists in cultivating Curtis’ physical endurance, his mentorship remains supplementary to Simon’s scientific tutelage and Otho’s tactical instruction.

Grag’s personality exudes a straightforward, amiable nature, underscored by a playful rivalry with Otho that frequently escalates into contests of strength versus agility or shape-shifting finesse. Despite occasional clashes, their synergy remains vital to the team’s unity. Later, Grag adopts Eek, a robotic owl companion, showcasing his capacity for nurturing bonds despite his mechanical origins.

Across adaptations like the 1978 anime series, Grag consistently serves as a loyal enforcer, tackling missions demanding brute strength, defense, and overcoming physical barriers. While his core traits remain unchanged, his interactions with the team persistently highlight themes of camaraderie and the nuanced humanity within artificial beings.