From the Masters of the Universe Origins Toyline.

King Grayskull is a character from the Masters of the Universe universe, particularly featured in the Masters of the Universe: Revelation animated series. He is an important figure in the lore of He-Man and Eternia, though his role and identity evolve in different continuities. In the context of Masters of the Universe: Revelation (2021), King Grayskull plays a significant role in the backstory of He-Man and the power of Grayskull itself.