Quote Originally Posted by Pramxnim View Post
I think it should be split off like the Lyric Thaumaturge. Usually PrCs don't bother with 0 lvl spells, since those don't come into use much anyways (and they can't be used to fuel Slot Burn).

So, I'd suggest something like:

At 1st level, the Furious Evoker gains one additional spell slot for his 1st, 2nd and 3rd level spells (since those are the ones that he can cast as he enters the class).

At 4th level, the Furious Evoker gains one additional spell slot for his 4th and 5th level spells

At 7st level, the Furious Evoker gains one additional spell slot for his 6th and 7th level spells

At 10th level, the Furious Evoker gains one additional spell slot for his 8th and 9th level spells (though he won't be able to cast them just yet if he went Sorc 5/FE 10)

These additional spell slots don't grant the FE the ability to cast spells higher than a Sorc of his class level (Only levels that grant Arcane Spellcasting count) could normally cast (even if by some obscure means the player secures the ability to know 9th level spells by that point, so as to prevent munchkin shenanigans).
Hmm, I like it but the progression is slightly irregular.

How about if the slots come at like this;
Level 2: 1st & 2nd
Level 4: 3rd & 4th
Level 6: 5th & 6th
Level 8: 7th & 8th
Level 10: 9th & 10th (if epic rules are used)