You become living flame, giving you fire immunity, resistance 10 to precision damage, and weakness 5 to cold and to water. Any creature that touches you or damages you with an unarmed attack or non-reach melee weapon takes 3d6 fire damage.
Your unarmed attacks deal an additional 1d4 fire damage, and your fire spells deal one additional die of fire damage (of the same damage die the spell uses). You can cast Ignition as an innate spell; the casting is reduced from 2 actions to 1.
In fire form, you have a fly Speed of 40 feet and don't need to breathe.
Spell Effect: Fiery Body
Heightened (9th) Creatures touching you take 4d6 fire damage instead of 3d6, your unarmed attacks deal 2d4 additional fire damage, and you have a fly Speed of 60 feet.
Traits
An action with this trait requires a degree of mental concentration and discipline.
Effects with the fire trait deal fire damage, or either conjure or manipulate fire. Those that manipulate fire have no effect in an area without fire. Creatures with this trait consist primarily of fire or have a connection to magical fire.
You must physically manipulate an item or make gestures to use an action with this trait. Creatures without a suitable appendage can't perform actions with this trait. Manipulate actions often trigger reactions.
These effects completely transform the target into a new form. A target can't be under the effect of more than one polymorph at a time. If it comes under the effect of another, the second effect attempts to counteract the first. If it succeeds, it takes effect, and if it fails, the spell has no effect on that target. Any Strikes granted by a polymorph effect are magical. Unless otherwise stated, polymorph spells don't allow the target to take on the appearance of a specific individual creature. If you take on a battle form with a polymorph spell, the special statistics can be adjusted only by circumstance bonuses, status bonuses, and penalties. Unless otherwise noted, the battle form prevents you from casting spells, speaking, and using most manipulate actions that require hands. (If there's doubt about whether you can use an action, the GM decides.) Your gear is absorbed into you; the constant abilities of your gear still function, but you can't activate any items. You lose your Speeds and gain those of the battle form. If a polymorph effect causes you to increase in size, you must have space to expand into or the effect is disrupted.