Goryōjin

A goryōjin (, goryōjin) is a human who became a god, similar to Tenjin. Not much is known about them currently.

Ebisu theorized that Father is a goryōjin, stating that his grave must still exist.

Goryō
The term goryōjin seems to be a variant of goryō (, lit. "honorable spirit"), considering Ebisu came to this conclusion after jokingly saying that Tenjin might be the Crafter due to the fact that they showed up around the same time.

Goryō were vengeful spirits (, onryō) that were honored after their death due to fear of their wrath. In pre-modern Japan, it was believed that rampaging deities, demons, and restless spirits such as onryō were causes of societal unrest, wars, natural disasters, and epidemics, thus the need to placate them. In Father and Tenjin's time - the Heian period - goryō were most often the souls of aristocrats caught in political intrigues; Tenjin (Sugawara no Michizane) himself is considered a goryō.

Adaptation Notes

 * While fast-moon's fan translation opted to leave the term as it is in the original text (romanized as "goryoujin"), the official translated chose to entirely omit it and approximate the meaning of the term.
 * Fast-moon: "...The Sorcerer was a human who died 1,100 years ago and carried a grudge with him to the grave, a goryoujin."
 * Official translation: "The Crafter is a human with a grudge who died 1,100 years ago. In other words, he was deified to quell his wrath."