The phrase "celestial brush" refers to a magical tool or power in Japanese folklore and video games. It allows you to paint or draw on the sky or reality itself, creating various effects or manipulating the world. Full definition
Issun is a traveling artist who, at first, only tagged along to learn the 13 Celestial Brush techniques but then developed a deep friendship with Amaterasu. (gonintendo.com)
It's time to play catch up with Capcom's series of Celestial Brush and Demon Introduction clips for Okami HD, which have been trickling out as we build up to the December launch of the latest remaster. (crunchyroll.com)