Portraits revealed through your current reading position.
Murderbot's absent research-transport friend, whose body-modification templates still help it pass as human.
ART—the powerful, media-obsessed research-transport intelligence that once remade Murderbot's body so it could pass as human and became its truest friend—remains off-page in book four, but its influence persists. On the trip to HaveRatton Station, Murderbot uses ART's stored templates to accelerate its own hair growth by another two centimeters, further softening its resemblance to a standard SecUnit, and reflects on ART's earlier subtle alterations to its limbs, skin, and body hair. Murderbot still carries ART's comm interface and misses it, though ART is nowhere near.
Bodiless: a vast feed-presence inhabiting a modular research vessel; not physically present this book so far.
Absent ally; source of the body-modification tech that keeps Murderbot disguised.
Also appears in books you've already read — spoiler-safe to their endings: