Dragon Ball Super fans have been drawn to Jiren during the Tournament of Power because he's different from the average foe. Often playing it cool to the point of seeming disinterest, fans have been trying to get at the core of the character just as much as Goku and Vegeta have.
Episode 122 may not have shed too much light on the character, Vegeta's prideful challenge to him did lead to Jiren showing more of a personable side as he recognized Vegeta's power.
Jiren has been aloof for the majority of the Tournament, even meditating through a good chunk of it, and his only real drawn into the battle was in his fight with Ultra Instinct Goku. He was prepared to fight Goku again, but Vegeta stepped in and proved to be more of a challenge than Jiren thought. It wasn't an immediate challenge, as Jiren easily swatted Vegeta away like a fly, but Vegeta improves mid fight just as he's done with foes in the past.
After dodging a flurry of punches and landing a few hits himself, Vegeta eventually charges a Final Flash attack. He balks at the idea of Ultra Instinct and vows to find his own new level of power, as Jiren insults his fists as "arrogant." Vegeta's Saiyan pride and blood could bring him to Jiren's level sooner rather than later, but unfortunately now's not the time.
Impressive as the Final Flash was, Jiren still took it head on. It could even be an acknowledgement of power that Jiren chose to block rather than to let it hit him without taking a stance. It even managed to knock Jiren for an instant, but Jiren showed how much he acknowledged Vegeta as a threat by putting him down with an overt showing of power.
Jiren hasn't been showing displaying much effort in these fights unless it's with strong warriors like Goku, Hit, and now Vegeta has joined those ranks. As the Tournament of Power whittles down to its last eight minutes however, who knows how much the two's powers could shift.
Dragon Ball Super's “Universal Survival” arc is part of the recent simulcast agreement that sites like Crunchyroll and Funimation have scored. DragonBall Super airs on Crunchyroll Saturday evenings at 7:15 p.m. CST. Adult Swim airs the English dub during its Toonami block Saturday evenings at 9:30 p.m, and is now available to stream on FunimationNOW and Amazon Video.
There is also currently a new Dragon Ball film in the works for 2018. The film will focus on the Saiyans, the "origins of Goku's power," and potentially the story of the very first Super Saiyan God.Not only does it aim to be the best film in the series, original creator Akira Toriyama will be contributing to the film's script and new character designs.