Locke is an ancient esper of unknown origins who claims no memory of his birth. Existing for over a century, possibly a millennium, he maintains the physical appearance of a youth, often perceived as a teenage boy with distinctive green hair. This eternal youth stems from a regenerative ability called "waka-gaeri," allowing him to periodically revert to a child form. He sometimes uses this process to be adopted by families, though it may also serve to avoid responsibility.

Initially living reclusively as a shepherd, Locke avoids galactic conflicts despite possessing immense psychic abilities. These powers include interstellar teleportation, telekinesis, rapid healing (psychogenesis), telepathy, energy barrier creation, and projecting energy spears. He denies the title "Locke the Superman," though others use it widely. An alternate identity, Liza or Eliza, emerges occasionally, once manifesting as a pop star.

Locke's background intersects with key historical events. During the Christian era, he interacted with figures like Wang Zhi Ming and Tatjana Klochkov. In the Universal era, he learned teleportation from Erika, an esper ancestor who challenged Earth forces. His relationship with Lianna Migault, who cared for him during a child phase, ended tragically due to nuclear fallout. Later, he aided the Ronwall independence movement, working alongside Julius Flay and Elaine Bernstein. Julius was assassinated after victory, and Elaine became aware of Locke’s true nature. Family ties include Machiko Grace, a cyber developer and sister-in-law, who involved him in experiments such as creating a body for the sentient fetus Lemus.

Character development shows Locke evolving from detached observer to reluctant participant. When Colonel Yamaki recruits him to investigate Lady Kahn’s esper army, Locke initially refuses until preemptive attacks force his involvement. Confrontations with Kahn’s operatives, like Cornelia Prim—who develops an attraction—reveal his strategic prowess. A pivotal subplot involves Jessica, Kahn’s prodigy brainwashed into believing Locke murdered her parents. Her romance with Yamaki and eventual alliance with Locke, after discovering Kahn’s manipulation, illustrate his capacity to forge connections despite inherent loneliness.

The climax aboard Lady Kahn’s sphere requires Locke and his adversaries to unite against an external threat, showcasing his shift toward cooperation. Across his journey, Locke embodies a tension between solitary immortality and impactful intervention, culminating in actions that shape galactic history while preserving his enigmatic essence.