In the anime, Kagetane's Heel–Face Turn makes more sense when you realize that his story arc was all about forcing his view point about what he thought the world should be like, and his conflict with Rentaro was about deciding the fate of the world. Rentaro wins, meaning his world is the current one. Kagetane's Heel–Face Turn occurs because he wants to see if Rentaro can maintain his world, and likely the minute it slips, he'll betray him.
The end of episode 7 was an absolute LOLWTF moment for me. To recap: Rentaro somehow wins against Tina thanks to a flashbang grenade going off at just the same time, and he knocks her unconscious. Afterwards, he carries her out of the building but she gets shot by Yasuwaki, who then has his underlings hold Rentaro down in a scene that brought up very uncomfortable memories of Sword Art Online. However, Seitenshi shows up and reveals that she knew all along that Yasuwaki would act on his own and then raises Rentaro to a high Contractor rank, meaning he outranks Yasuwaki. Rentaro proceeds to immediately shoot Yasuwaki's finger off and then says if he doesn't leave he'll kill him. At the end, Kisara reveals she hired Tina for the Tendo Agency, apparently meaning Tina got to walk free. Huh? Yasuwaki is a grade-A dick, but he looks Unintentionally Sympathetic here. Tina, cute as she is, attempted to assassinate the leader of the country twice. I think that's grounds for instant execution in some societies today, not even taking into account a post-apocalyptic police state. His reasons for doing it make sense when you realize his jealousy of Rentaro for taking his place as Seitenshi's personal bodyguard; he probably thought Rentaro was going to kill Tina first and attempted to Kill Steal him. Low, but his argument of Rentaro being Seitenshi's favorite holds water when Seitenshi gives Rentaro whatever he wants (a raise of 1,000 ranks) for what he did! Jerkass Has a Point, Seitenshi showed favoritism toward Rentaro over her professionally trained bodyguards who had spent years in her service! The icing on the top is when Tina gets away with no prison sentence or even punishment for her assassination attempts on Seitenshi! I understand the writer wanted to make his despicable villain cross the Moral Event Horizon here, but this was the wrong way to do it!
Except you're forgetting one thing- regardless of whether or not Tina should've gotten off completely scott-free, in that moment, the decision was not up to Rentaro or Yasuwaki. Tina was no longer a direct threat to Seitenshi, and bodyguards are not executioners. Furthermore, it was clear Yasuwaki was not acting out of concern for Seitenshi, but out of pure spite towards Rentaro. He even left Seitenshi at the meeting specifically to find Rentaro and ruin his day. Yasuwaki was not acting out of concern for Seitenshi, he was not acting within his position, and all Seitenshi saw was a jealous, deranged psychopath who tried to murder a young girl to settle a petty dispute about his job.
