Ikaron can first be encountered guarding The Hollow at the Druid Grove.
If the party lets Barth slap Meli for stealing his locket, Ikaron will call out the behaviour and challenge Barth.
If the Goblins from the Goblin Camp are defeated and the Tiefling Refugees have left the Grove for the campsite, he can be found at the Campsite away from the celebration, annoyed that the others are partying instead of grieving their fallen comrades. If the player character passes a Charisma check, he can be convinced to join the celebration anyway.
If Ikaron survives the events at Emerald Grove, his body can be found in the Shadow-Cursed LandsX: -9 Y: 54 among the Tiefling refugees that did not make it to Last Light Inn.