Diafthorá

"Just like a coin, everything, everyone, has two sides to them. Light and darkness. Good and evil. Blank and grey. It all depends on what your heart shows...and hides."

- A description of the Celestial Spirits and their Eclipse Forms Diafthorá (天体日食振興 (ダイアフトールア) Daiafutōrua; Greek for "Corruption", Japanese for "Celestial Eclipse Promotion"), alternatively known as simply Eclipse Form (食形, Shoku Katachi), is a Celestial Spirit Magic spell that triggers a transformation to their Celestial Spirits, granting them a change in appearance and greater power than before, at the cost of the Celestial Spirits sanity, as well as a completely different personality that could prove to be detrimental to the user. Due to the spell's side-effects, it is rarely, if ever, used by anyone who knows of its existence, and is infact considered forbidden among the Celestial Spirits, as ruled by the Spirit King himself.

Trivia

 * The concept is inspired by a anime-only arc, but due to the author never watching the filler, and only taking the alternate form into context, it will more than likely differentiate from the established filler.