rushlight
Roll for Initiative!
Thanks for everyone's input! It helped a great deal. I finally decided to assign spellfire a saving throw. Bascially, when he readies to absorb a charge he must make a Fort save (since spellfire is based strongly in Con) of DC 10+twice the number of spellfire levels he's about to absorb. Success means the levels are absorbed, failure will cause him to take damage (1d6 per level attempted...). This will limit his "invulnerability" to magic during combat, as well as his ability to deal with 9th level spells the same as 1st level spells.
Second, any use of the spellfire will require a Fort save of DC 10+the number of spellfire levels used. This will limit his ability to do mass amounts of damage during combat. The way I figure he'll be able to have an average chance (this is a 9th level party) to do around 5 to 6d6 points of damage without serious danger. That's about average for a 9th level party, so it's not unbalancing. Sure, he COULD do 18d6 (full dump!) but he'd have to roll a 20 on the save or take the damage himself... He could also dole the damage out in much smaller quantities with relative ease.
Also, you'll notice that he won't be able to just "recharge" every night for basically nothing. If he's using an item to recharge, he's going to have to take time or it gets risky. Also, the other magic users aren't going to save large amounts of low level spells just to beef him up.
Anyway, I talked with my player, and he agreed that these conditions were acceptable. I think it makes spellfire much more playable, with the character "learning" to handle this amazing ability as he matures. As opposed to him springing from the womb fully prepaired to absorb two Power Word Kills and then toss back 18d6 of damage. I really like the growth curve, and the realization of his full power.
Second, any use of the spellfire will require a Fort save of DC 10+the number of spellfire levels used. This will limit his ability to do mass amounts of damage during combat. The way I figure he'll be able to have an average chance (this is a 9th level party) to do around 5 to 6d6 points of damage without serious danger. That's about average for a 9th level party, so it's not unbalancing. Sure, he COULD do 18d6 (full dump!) but he'd have to roll a 20 on the save or take the damage himself... He could also dole the damage out in much smaller quantities with relative ease.
Also, you'll notice that he won't be able to just "recharge" every night for basically nothing. If he's using an item to recharge, he's going to have to take time or it gets risky. Also, the other magic users aren't going to save large amounts of low level spells just to beef him up.
Anyway, I talked with my player, and he agreed that these conditions were acceptable. I think it makes spellfire much more playable, with the character "learning" to handle this amazing ability as he matures. As opposed to him springing from the womb fully prepaired to absorb two Power Word Kills and then toss back 18d6 of damage. I really like the growth curve, and the realization of his full power.