Hircine, not the most powerful prince, faced off with the reincarnation of Lord Nerevar, the one who killed Dagoth Ur and Almelexia. He said "Facing me in all my glory would be less than sporting of me."
To sum up The CoC > Jyggalag > Hircine >> Nerevarine => CoC >>>> Nerevarine.
Am I missing something?
Note: My opinion is that the Nerevarine is a lot stronger than the CoC.