Echo of Sebilis  

The Echo of Sebilis is not KOS and does not assist other mobs. It seems to have many, many PHs in the lower area of Sebilis -- perhaps any myconid, froglok, or juggernaut. Just clear the area of mobs and you will eventually spawn it.

As of June 2018 patch, this NPC will not spawn on progression servers until Gates of Discord is unlocked.