what.
sex is a terrible way to mana transfer. if you summoned a creature, whatever contract you signed with them should probably act as a medium for mana. if you're giving another human mana, either they should know how to receive mana(caster), or just not need mana at all(non-caster).
and in...
the massive timeskips feel like the author is going
"Alright an event happened"
"Alright another event happened"
It's like a game with just boss fights. Boss fight, the moment it ends you're fighting somebody else, and then the next guy, and the next and next. You don't even know their names or...