Siar was founder of Abel and Aniz's clan; her affinity was Woe, which may have overlapped with Seme's affinity in the present day (despair). Little is known about her at the time of writing other than her arrogance (she took Fa'Lina's one-by-one strategy of saving young cubi as a sign of weakness, according to Aniz) and her love for Seme before she was killed by the Dragon Hizell. She was not his only victim; Jin's two sisters and their clans were also destroyed by him. Dimanika's sister and Hrienth may also have been killed by him, but at the time of writing that is unknown. He may have also been the dragon who killed Fa'Lina's clan, which would make him the father of Pyroduck (the Dimanika Clan gave Pyroduck and his siblings to the suriving cubi their father had hurt; even if the father was Hizell, Siar was no longer alive at that point). Siar's clan was fortunate enough to survive her fall (although the remaining members after she fell may disagree with that other than Abel, who never knew her), unlike with Jin's two sister clans, but all the survivors had mental scars from their leader's death. Only Aniz remained a living clan member, as Sel converted herself and her son to Seme's clan and Elin committed suicide. With Aniz dead and May having never been made a cubi (impossible without Siar's help), Abel is the only known clan member alive, but in the period of over three hundred years between Abel's admittance to SAIA and Aniz's death at the hands of Quintinga Ti'Fiona, Aniz had ample time to have more children, although he might have been waiting to sire a child 24 years before the time he could admit one instead of 27 (Alexsi Ti'Fiona's age and the latest he could have fathered a child before he was killed).

eras: at least 400 years before canon, before Aniz left SAIA and Abel was born.

Reference links:

Aniz mentions Siar clan's arrogance, implying Siar had an excess of hubris (then again, challenging Hizell implied she had an excess of hubris): Abel's Story, Part Two, Page Seventeen

Seme's page in Mink's Clan leaders report reveals Siar also had a loving side and was kind enough for Seme to mourn for her as long as she lives, turning her wings black in grief.