Forseti Sibyl is an elf that lives in Gehenna. She is the elder sister of Tegwen Sibyl, and works at the Gehenna Town Welfare Center. Forseti has a very dry sense of humour and seems very serious, as she prioritizes work over the "strange presence" that Tegwen sensed during the arrival of Preston Omid to Gehenna.

With her strong sense of justice, Forseti was an optimum candidate for the Gehenna Police Force, however, due to prior run-ins with the law, she was rejected and instead sent to work at the Gehenna Town Welfare Center. Forseti Sibyl is somewhat notorious for leading the crowd who dragged "The Last Rapist of Gehenna" out onto the street to be executed by H.E.L.L.S.I.N.G. agents eight years ago. Following this, she said that the vampire killed would serve as "an example to all who would dare violate the indisputable right to bodily autonomy in our community". When asked if she would do it again, she said "gladly".