Oh don't worry about Epic Spellcasting Sunking banned that on day 1
You shouldn't worry too much about magic, here are all the immunities we get:
A deity is immune to polymorphing, petrification, or any other attack that alters its form, Energy Drain, Ability Drain, Ability Damage, Mind-Affecting Effects,
Deities of rank 1 or higher are also immune to electricity, cold, acid, disease, poison,
stunning, sleep, paralysis, death effects and disintegration.
Deities of rank 6 or higher are immune to effects that imprison or banish them. Such effects include banishment, binding, dimensional anchor, dismissal, imprisonment, repulsion
You also get a lot of Spell Resistance. So a caster can't do that much without Epic Spells. He can Time Stop (which you can easily get as a SLA), Gate in some fodder Demons or Angels, and possibly target you with a Vitriolic Orb (which is a SC spell anyway so he probably won't have it).
Meanwhile you have tons of HP, high saves and attack for 6 or 7 attacks per round with impressive BAB.
What could potentially get you is a bad Will save vs Divine Bardic Music

D), another Deity killing you with his own stick +6, or Salient abilities. And of course, deities with a higher DR.