Sialeeds was the younger daughter of Queen Falzrahm and her husband Kauss, a member of the Barows Faction. In her youth she was arranged to be married to Gizel Godwin but in the aftermath of the Falenan succession crisis and the Armes Invasion, the relatives of the newly crowned Arshtat agreed not to marry in order to avoid a repeat of those struggles. It is around this time that Sialeeds started dyeing her white hair, to distance herself from the royal line.
She served under her sister, performing inspections around the country and generally living a care-free, if slightly directionless, lifestyle. When the Sun Rune War broke out, she escaped with the Prince and Georg Prime, helping to form the Imperial City Recapture Army and providing counsel, particularly when it came to noble political matters, a subject in which she was well versed. She begrudgingly agreed that Lucretia Merces would be a valuable asset to the army, having harboured resentment towards the tactician for years due to her role in persuading Arshtat to bear the Sun Rune.
As the war dragged on, although she believed in her nephew's cause, she also decided that he lacked the nous to sweep away the corrupt political structure even if he should win the war. So, when Queen Lymsleia Falenas was on the verge of being rescued, Sialeeds would betray her comrades, taking her back to her Godwin captors. Some time after, she would inherit the Twilight Rune from Alenia.
When the Prince's army marched on Stormfist, Sialeeds was sent to guard the city. Sialeeds used the Twilight Rune on behalf of her former allies, thwarting Childerich’s ambush in the arena but also against them in battle, before returning to Sol-Falena. Following this, Sialeeds traveled to Rainwall, where she met with Salum and Euram Barows. There, she killed Salum, bringing her plan to remove both the Barows and Godwins from power one step closer to completion.
When the Imperial City Recapture Army brought the full weight of its force down on Sol-Falena, Sialeeds confronted her nephew at the Sol-Falena Dam. The Prince and Lyon attempted to prevent Sialeeds from using her rune, but any plans of capturing Sialeeds were put on hold as the Godwins used the Sun Rune to destroy the dam. Aunt and nephew used the combined power of the Twilight and Dawn Runes to protect themselves and Lyon and were able to seal the Sun Rune for a time.
However, Sialeeds used up the last of her strength doing this, and the Twilight Rune left her for Lyon. Sialeeds knew she was dying and urged her nephew to continue on. After the Prince and Lyon left, Lucretia came to Sialeed's side. Sialeeds confessed her plan to Lucretia, who replied that she understood Sialeed's motivations but that, in the end, her logic was no different than the Godwins. In reply, Sialeeds used her final words to express how much she disliked Lucretia.
After her death, Sialeeds was buried at the castle in Ceras Lake, unable to be interred with the rest of the royal family due to her betrayal. Following the defeat of the Sun Rune incarnation, Sialeeds was briefly seen as a spirit in the Sun Rune, cheering on her nephew.
- Gensosuikoden Kiwami Encyclopedia, pages 601-2