How do I increase spirit?
You want stuff like kotone's blessing and nymphs blessing, those two are pretty much cost free(though you get hypno slave and have to eiither rise to lover or abort her route) also on easy I think you can flat out boost it?- Oh, And there are three perks you can get by level up that each give you one too, Personally I have 11 on a maxed character.(I bulit that one on allure first power second, well equip wise, I kept stats pretty balanced till they were all 40, then i invested in the important ones,) Tl;Dr you can expect to get11 without much drawbacks.