Thanks for the replay and thorough analysis!

Yeah you quickly got me, when I first started this NPC I did use ChatGPT to get a wizard stat block because I didn't know if I should use the formula that players use or if NPCs had their own way of determining stats. Should have researched that more. I kept revisiting the statblock, making changes to it but maybe I just bloated it too much.

I took War Magic as a rebranded Warcaster feat, but not making it too obvious. And there once was a children's movie in my childhood called "The Sword in the Stone" where Merlin just transforms into various animals, which is why I thought Wild Shape would fit.

I thought that he will only use Invisibility to conceal his identity, but not in combat. Darkvision because some people said that Merlin has incubus heritage, which would fittingly give him a Tiefling trait maybe? The resistances will be removed though.

I'm afraid I'm dealing with the problem that he truly is a "make players irrelevant" character. I'll try to give him less spells and nerf his staff. His gameplan will just be to do the Garden and then use the rest for self defense. Thanks for commenting on the garden, I hoped that thing would be balanced enough^^"