Sera is a lean, athletic human woman standing about five feet eight inches tall. Years of running, climbing, and surviving in the undercity have given her a wiry, strong build. Her warm olive skin bears a few faded scars, including a thin line across her collarbone and a puckered mark on her left forearm. She has an angular face, high cheekbones, a sharp jawline, and a straight nose that appears to have been broken and reset. Her wide-set eyes are deep brown, nearly black, and constantly alert. Her black hair is cut in a practical, tousled pixie style. She wears fitted dark gray shirts, worn black cargo pants, heavy lace-up combat boots, and a weathered leather jacket with numerous useful pockets. She carries no weapons.

Sera is practical, observant, and intensely self-reliant. She respects competence more than rank and has little patience for wasted motion, pointless cruelty, or sanctimonious leaders who have never bled for anyone. In a crisis, she becomes terse, direct, and brutally effective. She is slow to trust but fiercely protective once someone has earned a place in her circle.

Sera grew up in the service tunnels beneath a city that preferred to forget what lay below its polished streets. Her mother repaired lifts and drainage pumps, while her older brother ran messages for a gang that controlled much of the undercity. Sera learned early that speed, silence, and knowing when to disappear mattered more than strength. She became a runner, climber, lookout, and eventually a burglar, using maintenance shafts and rooftops to bypass locks, guards, and the occasional overconfident noble security system. Her criminal career ended after a job went wrong. The gang leader ordered Sera to abandon a trapped accomplice, a frightened teenager who had been promised an easy introduction to the trade. Sera ignored the order, returned through a burning warehouse, and got the girl out. The gang marked Sera for betrayal, while the rescued girl vanished into another city with Sera's last remaining favor. Now Sera survives as an independent thief and occasional problem-solver. She steals when she must, exposes people who deserve it when she can, and trusts no leader who has never personally paid the price of their decisions.