TheWoWDBRare
Heimir of the Black Fist
King of the Tideskorn
Details
This roster comes from the current game client's data files, so it is not a complete list of every NPC in the game - older world NPCs that are no longer in the modern client are absent.
Level and Map Tracking
The game data tunes Heimir of the Black Fist for level 50, Battle for Azeroth content.
The map marks it with vignette 3,648, which the client hides once hidden tracking quest 56059 is complete. In game, /run print(C_QuestLog.IsQuestFlaggedCompleted(56059)) prints true when that quest is flagged for your character.