Therkla's Island is a name given to the remote island in the ocean where Therkla and Elan met in secret away from the Azure fleet. Unbeknownst to Elan, Lien was aware of their plans and she along with Hinjo, Durkon, and Vaarsuvius set a trap for Therkla by V casting Veil to make them appear to be trees. When they tried to take Therkla and Qarr into custody, Qarr summoned a monstrous Pit Fiend from the hells. In the ensuing battle, Therkla escapes with Elan in tail to go back to the fleet to foil Kubota's attempt to extinguish House Kato. Qarr also escapes in the confusion. The paladins are unable to do much damage to the pit fiend, but V and Durkon lower its resistances and V manages to petrify the beast with a Prismatic Spray.
The next day, Elan returns to the island alone to bury Therkla at the foot of the pit fiend statue, carving her epitaph into the stone.