Going off the the assumed build of Wizard 3/Incantatrix 10/Initiate of the Sevenfold Veil 7 (as mentioned on page 1), and the further assumption of rebuilding (which ironically only needs to happen once at 6th level), what's the easiest course to create a firemage out of this? Combining "I'm invincible" with "and you're on fire" just seems like WAY too much fun, and he won't be lacking for buffage/debuffage/BFC either (he's an Incantatrix of the Sevenfold Veil FFS!), so consider about 80% of resources available for burninating and action abuse.