The OP is referring to the "
Find Doni" quest, which is only available
during battle preparations against Minthara's raid.
Nothing to do with Mirkon, as this particular quest breaks
if Marcoryl (the Karen druid kissing up to Kagha) dies. The quest has no failsafe in place to properly account for his death so because of this Doni can't be interacted with to complete it (only way to complete the quest is to lure him to Rikka via
Minor Illusion). Has also been covered in proper detail here;
[BUG] - Find Doni Quest Progress Blocked