HolyC is TempleOS's primary language. Previous to its creation the author had a mental breakdown... this should explain everything quite clearly https://en.wikipedia.org/wiki/TempleOS
TempleOS was an OS created by a genius programmer named Terry. Also, I very rarely use the word genius, but he was a genius by definition. He was extremely mentally ill, but his brilliance lives on through TempleOS (and HolyC). Check out this Down the Rabbit Hole video about him.