She doesn't want to die.
Or, at least, she shouldn't. They wouldn't want her to die. Nari never agreed with the council's decision to pressure those without ties into making Artefacts.
But Nari is dead. So is Kané, and part of Bira can hardly believe she mourns him, but his death shook her just as much as their childhood friend's. Without either of them to ground her, to remind her of what was important in this hellsscape of a war, the council's arguments seem more and more reasonable.
Wouldn't it be easier, to move on? Leave her power and her current personality to help those left behind, and take her memories of her lost loved ones with her into the void? Wouldn't it be better to go on her own terms, leaving behind her legacy for those still fighting, rather than die on the battlefield and take everything with her?
It's only a matter of time, now. She knows she's been getting more and more reckless as time goes on, without Kané to guard her back, or Nari to remind her to be careful. There's no one else, no reason for her to stay, to keep on fighting the Taimos, following them from world to world, trying to hold back a tide of enemies which seems unending.
She wants to see them again. To stand at their sides and know she has a place, a purpose. That's all she ever wanted.
Before her is a knife, and a long, shallow trough. This is all that is needed for the ritual - a sharp edge to make the cut, and a basin for the blood. Resolved, she reaches for the knife, taking it with her as she steps into the trough, sinking to her knees. Closing her eyes to block out the watchers, surrounding her against the walls of the room, she slides the knife between her thighs, and closes her legs just enough to feel the bite of the sharp steel.
With one last prayer offered to the void, she draws up as much of her pool of mana as she can wind into a single chord, squeezes her thighs tight, and jerks her hands up, severing both femoral arteries.
Blood gushes out, and she immediately slumps forward, the pain easily being outcompeted by woozy drowsiness. Her vision clouds remarkably quickly.
Her last thought, before she loses consciousness, is of Kané, wondering how long he took to die when he did this himself.