Talk:Tier Magic/@comment-58.108.203.65-20180818110820/@comment-45.56.46.26-20180821055059

It may not be the case that every class (or even every caster class) has unique spells, and it seems that most spells are not unique to any particular class but can be learned by many or classes which have the right general category (arcane/divine/spiritual/alternative).

But yes, it seems likely that you need the right class to learn a spell when leveling up. It is not clear whether you need to be gaining a level of that specific class, or whether you can learn it by already having the class even if you are gaining a level in a different class.

In any case, caster levels affect mana and caster level, so even if a mixed build with only a few casting levels could learn lots of spells, they would be of sharply limited utility. Momonga is amazing for having learned over 700 spells (compared to the usual 300 cap for a max level player), but simply knowing that many spells doesn't place him in the top tier of players, so just knowing a lot of spells isn't everything.