Rosa

The sun-watcher of The Foredweller Research Facility. A small, glasses-shoving scientist who works alone behind a locked half-door in the facility's control window, recording — minute by minute, for months — the state of two Foredweller lights (green on, red off) and the position of a lever she believes controls the sun. A year underground has isolated her from her colleagues entirely; her office wall is a red-string collage of the sun, the moon, and fire-domain pyromancy, and the rest of the team openly calls her an idiot.

She is also, as far as anyone can prove, half right.

Session 53

• The theory. Every watch the team brought down averages 6:11 PM; the lever sits at 31% up; that leaves 30% of the day until the witching hour at 2 AM. She has watched it rise with the sunrise and fall with the sunset for months. The single glyph the facility's chief translator has cracked, engraved above the lever's up-setting, means something close to light or dawn. She refuses to touch it: "if the lever moved, it would be disastrous, for the sun would turn off." Two people have charged the lever to yank it; both were too weak to move it, which she counts as a mercy.
• Burned her scroll on a stranger's hunch. When Lash explains that she needs sunlight to use the sun-symbol burned into her mind, Rosa produces the spell scroll of sunlight she has spent the year studying and spends it without hesitation — "No, no, I'm fully in" — waving Lash into her office and taking notes throughout.
• Vindicated and refuted at once. Lash's sun-sight shows the symbol over the lever flickering with distant sunlight, matching the glyph in the library book: it really is a sun-thing, and it really does say dawn. But it is also a magical illusion disguised as an ordinary lever — which is why nobody, at any strength, has ever been able to pull it. Rosa ends the session running around her office with Lash, re-pinning red string.
• What she isn't trusted on. Dr. Xiao Li trusts each of her people in their own field and specifically excludes this one: "I don't trust Rosa on the sun either" — right up until Lash's evidence forces her to reconsider, and to conclude that this is one more reason nobody may ever be allowed down here.

Session 55

• She keeps the door. Rosa's control window sits beside the facility's main exit — the north door, past the sun lever — so when the party leaves it is Rosa who works the wall panel (a Fallout Pip-Boy-style control) and grinds it open on dust, crumbling rock and the darkness of the bored cave beyond. Lash knew where to wait because she had spent five hours in that office; her instinct that Rosa "watches the main door" is correct in both senses.