WARNING: The following contains spoilers for Boruto: Naruto Next Generations Episode 187, "Karma," now streaming on Crunchyroll.
The latest episode of Boruto cuts a tragic, sympathetic figure for Ao after it was revealed that he turned his back on the shinobi world, believing they'd repeat the mistakes of old. He betrayed Konoha, stealing scientific secrets for the Kara terrorists, and now, after killing Mugino, he's trying to end Team 7 so he can retrieve the Vessel for Jigen.
However, after a soul-stirring speech from Boruto, Ao finds redemption thanks to a heroic act. But sadly, he doesn't get to bask in the afterglow as he gets brutally murdered by the man overseeing the recovery mission.
After disabling Ao's drones, Boruto defeated the villain using a Rasengan but, rather than kill him to avenge Mugino, Boruto follows in his father's footsteps. Just like how Naruto redeemed Nagato, Obito Uchiha and so many others through lectures, or "talk no jutsu," Boruto makes it clear to Ao he should never have given up hope. While Kara turned his cybernetic frame into a tool, Boruto's adamant he always had a choice and, despite losing most of his body in the Kaguya War, Ao is still a person. Boruto leaves a screwdriver next to him, telling him it's time to fix himself and the past. As Ao sheds a tear at Boruto's unwavering faith, he quickly becomes fearful as he sees Koji Kashin perched on a statue.
And in the blink of an eye, the assassin summons his giant toad and leaps down to crush Boruto. Luckily, Ao uses a water jutsu and the deluge washes Boruto away, clearing him of the hit. Unfortunately, the toad squashes the lower half of Ao's body. As the life slowly leaves his body, Ao looks slightly relieved, confirming Boruto did convince him of the shinobi code once more. Koji ridicules him for it, however, deeming him a failure, not just for botching the mission, but for wanting to die a ninja again.
This infuriates Boruto and, after his squad battles Koji, barely escaping with their lives, they bury Ao. Konohamaru makes it clear he doesn't forgive him for murdering Mugino, but seeing as Ao, a Kirikgakura-nin, died an honorable death, they must pay him proper respect. It's the shinobi way, after all, which does inspire Boruto.
He felt deep down Ao could make amends, even if just by standing trial, admitting his wrongs and staying in jail. But seeing Koji as decided to play judge, jury and executioner, it's riled Boruto up, leaving him wanting revenge on Kara even more.