One crazy, messed-up lich
Ikar was once a high ranking member in the Cult of Thoresh under the tutelage of Bazuul Thoresh. The cult had perfected the unique ritual to bind devas as living phylacteries. This not only provided them with an unsuspecting vessel, but enabled them to move around in the form of the deva until they were strong enough to return to their own physical form. More importantly, the connection also gained them valuable knowledge from the deva’s many lifetimes.
Ikar killed his master after crazy dreams started haunting his sleepless rest. Volarn, a Kaorti knight who had been trapped in the Far Realm, was able to make a connection to Ikar for some reason, and filled his undead mind with twisted schemes and plans. At some point, Ikar found Bazuul’s agenda mundane and usurped his master. His plan: open a portal, rescue Volarn, and unleash aberrant creatures into the natural world.
The Fallcrest Fellowship has foiled his plans by closing the portal, destroying the Tear of Knowledge, and killing Volarn. Ikar escaped the heroes, but left behind his phylactery, a deva named Ailis Marzal. It’s a good guess that he knows his phylactery is still intact and that he has realized that he has to be very careful not to succumb to an fatal situations or find himself in the midst of his enemies.