Shin Megami Tensei III: Nocturne
The leader of the powerful and violent Mantra Demon Army, Gozu-Tennoh ruled from an imposing skyscraper in Ikebukuro. Despite his obvious strength, he relied on his Lieutenant Thor to enforce his rule, and was uninterested in using the power of Kagutsuchi to recreate the world. He and his Mantra vastly preferred the chaos of the unshaped Vortex World, which along with other ideological differences would lead them to clash with the Assembly of Nihilo.
He encountered the Demi-Fiend after the latter had trespassed within the Mantra headquarters and succeeded in winning his freedom through a brutal trial by combat. Impressed and seeking to convince the newcomer to become his ally, Gozu-Tennoh granted him an increase in power before they parted ways. He also decided that the time had finally arrived to march his army against the Assembly of Nihilo, meaning to crush their ambition and pride and prove the Mantra's superiority.
Believing that sheer force would prevail over all else, the Mantra swept in and crushed a base full of Nihilo at Ginza, only to realize too late that the battle was a simple diversion. The Nihilo used their secret weapon, the Nightmare System, to target the Mantra Headquarters remotely and drain the Magatsuchi straight from the demons' bodies. The Mantra fell into disorder, and Gozu-Tennoh was mortally wounded.
Cursing the Assembly of Nihilo to his last breath, he swore that he would not die, and would find some way to halt their plans. His body collapsed into rubble during his final talk with the Demi-Fiend, and would remain motionless until much time had passed and the dying Chiaki stumbled across his corpse.
His spirit stirred by the similarity between his own feelings and that of the dying human before him, Gozu-Tennoh reached out and spoke to Chiaki about their shared ideal for a world where the powerful ruled. Each lamented their own failings in bringing about their goal; while Gozu-Tennoh was mighty indeed he had no plans and was outsmarted easily. Chiaki, however, had ruthless cunning and ambition but lacked the strength to follow through. Realizing that their respective problems could be solved, Gozu-Tennoh gladly offered up his remaining energy to heal and empower Chiaki, making her into a being truly capable and worthy of ruling over the fractured Mantra, who would be reunited and become a far greater threat with the addition of a legion of divine Angels seeking to serve Chiaki's new Reason of Yosuga.