Thulsa is heavily involved in the story quests concerning the elve's home city of Allemantheia and the restoration of the Core powering the elven race. Thulsa's forces are causing trouble in Essenia, seeking to disrupt Allemantheia's defences. Thulsa sought to blame this unrest on the hero Kaidun, the partner of the elven leader Fraya. Adventurers were recruited to investigate the conflict, leading to the Necromancer Tomb and the revelation that Thulsa had trapped and imprisoned Kaidun.
Later, Thulsa is revealed to have infiltrated Allemantheia in the guise of the sorcerer Malachai in order to steal the Core. Adventurers teamed up with Fraya to defeat Thulsa, but he was saved at the last moment by Akasha. This resulted in a chase across Ostgarath, into the Golden Labyrinth and Akasha's Hideout in order to retrieve the Core and secure the stability of Allemantheia.
He later escaped to Northern Shara and attempted to wake Sikander as Kelsaik, allying with Killian and causing chaos in order to distract the federation from engaging him. However, due to the interference of the adventurer and Isrenia, Kelsaik awoke as a crazed beast, out of the control of Thulsa.