UltraBlazing Will is Will's primary version of an Ultra form.
Will the Echidna storyline
Book Four: Insanity
Will uses his UltraBlazing form to fight Phoenix with Blood in his Rage Demon form and Knuckles as Super Knuckles 4. Phoenix defeats all of them by powering up again, making Will power down and get approached by Flashfire, the leader of the Celestials and discovered how to ascend to his most powerful form: TrueChaos.
Book Six: Sealed
Will uses this form against Legendary Super Sayian Scourge, who defeats him easily, prompting him to Chaos.
This form of Will has more hair than his HyperBlazing form, but the same colors. However, after the update, it becomes closer to the revamped HyperBlazing style, with additional hair out the back, and sky-blue tips.
He has all the same abilitys as HyperBlazing Will, and has the most powerful Blazing Angel of any of Will's forms. He also has the ability Meteor Storm, similar to Chaos Firestorm, but much more powerful and dangerous. He can summon fireballs and can create magma flows at will.