Grimm and Nightmare King Grimm by Caronat on DeviantArt

Ira Wendagoth, Critical Role Wiki

Monster Analysis: Ira “The Nightmare King” Wendagoth (Moon Tower) — CritRoleStats

Troupe Master Grimm

The Nightmare King Commission Work by ChrisNazgul on DeviantArt

Grimm and Nightmare King by duke_of_dangers -- Fur Affinity [dot] net

ArtStation - Ira the Nightmare King

Nill Ichi - Nightmare King Grimm

Didn't realize the “Nightmare King” from BK was gonna be a literal nightmare. : r/ExpectationVsReality

The Last Kids on Earth and the Nightmare by Max Brallier

BK – Nightmare King — Andy + alex