Thought I would make some observations about Prince Charmless.
First, the upsides. He is as fast as Zyla, with a higher damage output (especially against non-Artifacts, since Epic Quest gives weakness to Nature and his other extra turn skills do Nature damage), and unlike Zyla he has more than enough extra turn skills to do what Volt does on defence. Including one with Poison DoT.
His Trait goes one up on Volt, just, since he is Hardened and immune to poison. His speed and damage output outclasses Volt.
He has a fearsome Special. Slightly less damaging than Zyla's (75 vs 80) but applies bleed.
The mixed: He has an attacker Classification and like Volt he can carry a Sword and Mask. Great relics for an attacker. I look for those relic slots on an attacker. But not so great for an extra Turner - no attacking stamina gain, only possibly a defensive stamina gain, which is not useful for an extra Turner. And although he has more life than Volt and Zyla, he still has low life.
The bad: if he is only in Good Legions... well, say hello to Tijen, handed out for free in a recent 72H challenge. Not only does she have Anticipation, but can also carry an Oblation Trap. And as noted, the Frog cannot regain stamina from Relics.
He has no 0 CD extra turn attack. Usually no problem, since he can rotate his extra turn attacks. But unlike Volt and Zyla, Cooldowns Activated will deny him.
His stamina costs are higher, a little, than Zyla - and, as mentioned, he has no Staff, Amulet, or Banner to top him up.
Certainly he is a very good monster. Possibly the best Race Monster, possibly the best Nature attacker. Aside from his vulnerability to Cooldowns Activated, he outclasses Volt. But I am not convinced he dethrones Zyla. His higher potential damage output and ability to keep going on defence are outweighed by his relatively inferior Trait and, mainly, the fact that energy drain relics will stop him dead in his tracks.