But what do you call the 4-person equivalent to a trinity?
Tetragrammaton - the 4-letter Holy and Unspeakable Name of God, in Judaism.
(Srsly,
I don't think there is a single word for trinity-plus-one -- power-sharing gets harder the more people are involved. "Fearsome Foursome" might work here...)
Well, since y'all are doing a mighty fine job at looking judgemental (an art Emil has mastered) we could just call it The Jury. Or the quadrumvirate.
EDIT: Ah, phooey -- Fimbulvarg proved me wrong! Curses, out-vocabularied by a NORWEGIAN!
*slinks away in shame*