"Vegeta: Kakarot backed him into a corner, and it seems the prospect of him losing made him relive all his trauma from his past.
Usage and Power
In this state, Jiren is referred to as being the Burning Ultimate Warrior (熱き究極戦士 Atsuki Kyūkyoku Senshi).
In the anime, Jiren took achieved this state when he broke through his limits in order to battle Ultra Instinct Goku. In this state, Jiren was capable of going toe-to-toe with Ultra Instinct Goku, gaining enough power to bypass the instantaneous defense impulse of Ultra Instinct and even initially overwhelming Goku in raw power. Even when Goku stood up to fight even after blasted down by a strengthened Power Impact, Jiren was still able to compete against Goku, although he was eventually overwhelmed, due to Goku becoming more powerful from his friends' faith in him. While he was still able to fend off Goku after Goku got angry, his newfound strength soon proved to be outclassed when he was savagely attacked by Goku, after he attacked his friends in the stands.
When he was greatly wounded by Android 17 in the waning moments of the tournament and nearly submitted, Jiren received words of encouragement from Top, allowing him to overcome the trauma of his past and regain his hidden power as result. However, even then, his strength was still overpowered by combined assault of Goku and Frieza, whom defeated him with the very last of their power.
In the manga, the exhausted Jiren achieved this state in response to being overwhelmed by Goku and Vegeta's teamwork, boasting that he had no limits and powering up, to Vegeta's shock. The boost in power allowed the exhausted Jiren to go from losing to Goku and Vegeta's assault to being able to charge through their combined Kamehameha-Gamma Burst Flash and knock Vegeta off stage, however he in turn was knocked off stage by Golden Frieza when he was distracted.
Video Game Appearances
In Caddass, this state is referred to as "Full Power".
In Dokkan Battle, this state was named "Burning Ultimate Warrior" and Jiren (Full Power), and appears as both a playable unit and a non-playable boss.
In Dragon Ball Heroes, this state was named "Super Full Power".