In which case it would be better to use Create Undead as a base, as it makes a specific monster based on your level. Plus there's the fact that the only Archon with actual cleric casting is the Trumpet, which is probably too powerful to summon at CR 14. Note that Create Greater Undead caps at CR 11 Devourers at level 20; and for this ability you'd probably want even weaker Archons since you can do it at will.