Miro was an early name used for the King of Eternia in the Masters of the Universe series bible who eventually became King Randor. When this tale about Randor's father was written, the name Miro was dusted off and used for the former king.
This story was released on VHS in the UK together with One for All (1984) and Revenge Is Never Sweet (1984).
The character of King Miro would appear again in King Miro's Journey (1985) King Miro and Price Adam visit Princess Adora on Etheria, Miro being grandfather to both Adam and Adora.
The animation of He-Man leaping and grabbing onto a ledge will be used again in Visitors from Earth (1985).
The interior backgrounds of Castle Fear were used earlier as those of Spydra's castle in The Return of Orko's Uncle (1983) and will be seen again inside Castle Landros in Bargain with Evil (1985).