Twilight Hermit is an NPC found in Silithus. It was first introduced in 8.0.1 BFA pre-patch as a beast with a human voice lines, however it got stealth hotfixed shortly and is now a humanoid with orc voice lines.
/way Silithus 40, 76.5
It seems that the https://www.wowhead.com/npc=132886/twilight-hermit is the NPC to which you hand in the https://www.wowhead.com/quest=53183/wriggling-mass quest that you can get in Island Expeditions.
For more info about Island Expeditions Rewards, check our guide here: https://warcraft-secrets.com/guides/island-expeditions-rewards