It's actually a neat trick to circumvent his 'morals'. He hates the archmage, but can't find anything he did particularly wrong to him or his acquaintances, and since he deliberately decided and proclaimed that he doesn't care about any justice or anything, only revenge - means he can't base his justifications on him being involved in slave trade etc. But he can give power to the girl, and the main condition is that the desire for revenge, the will and the reasoning aren't his. So he both preserves his morals and kills off the archmage.
Wow, our hero became a psychopath now. Honestly If the real world was this cruel and I had powers like MC, I would have done the same with a smile or giggles.
Wow, our hero became a psychopath now. Honestly If the real world was this cruel and I had powers like MC, I would have done the same with a smile or giggles.