A Delta Quadrant humanoid people whose deposed tyrant Tieran survived death by transferring his consciousness into Kes in order to reclaim power.
The Ilari are a Delta Quadrant humanoid species governed by a ruler known as the autarch. In Warlord, Voyager rescued three Ilari from a damaged ship, but the injured Tieran, a former autarch overthrown by his people, died in sickbay soon afterwards.
Tieran had in fact survived by moving his mind into Kes using a neural device. Controlling her body, he escaped Voyager and returned to the Ilari homeworld to retake power through assassination and force. The Voyager crew eventually reached Kes, and with Tuvok's help through a mind meld she forced Tieran's consciousness out, ending his return to rule.