What's the point of active skills when you can't get them before you beat the game completely? I guess if not for being a mage, a swordsman would have to afk grind for days or something, but a mage just easily beats it in less than 30 minutes with equipment. (with good luck and a good build you could prob beat the demon lord in under 10 minutes)
(Only beat the demon lord 5 times cause I didn't realize mage could beat it at rebirth 2, could've been 7 times, rip.)