VoidUzumaki

Did almost all existing side quests, explored the world map, decides to finally take on the main quest... uh, this is kind of easy.

Cat girls - I can already see catgirl or maid caffees popping up

why the max mana?

one could argue that he now creates actual crystals, which therefore don't need maintenance.

Where did that one come from?

This costs effectively the same as 4 times 5 slots or 2 times 10 slots. Shouldn't bulk get cheaper? Not necessarily linearly, but still.

Good way to handle temporary skills. Like it.

I actually thought your idea was 'make crystals -> sell crystals -> use money to increase skill -> make better crystals -> make more money' rinse and repeat

considering the story, my mind went there first, before thinking of horns.

MC has the same hair and eye color. Coincidence, I think not.