The battle between Seira J. Loyard and Rostere- the 10th Elder takes place when the Elders (Rostere and Muar) and Bonerre come face to face with Raizel and others. Rostere attempts a sneak attack on Frankenstein while he is fighting Muar but Seira blocks it. Then they both start to fight.
Raizel and M-21 go out to look for Tao and Takeo but suddenly come face-to-face with Rostere, Muar and Bonerre instead. Meanwhile, Seira, Regis and Frankenstein find Raizel missing and arrive at the place just in time to stop Raizel from using his powers against the Elders. Frankenstein takes on Muar and seeing the former gaining the upper hand, Rostere decides to finish off Frankenstein from behind. But his attack is blocked by Seira and their battle begins.
Rostere starts to insult Seira as the youngest and weakest clan leader. But Seira maintains her composure and rather asks him to fight than talk. Frankenstein complements her on the well-managed behavior and she blushes. Rostere becomes infuriated with her for daring to challenge him and proceeds to launch energy blasts. Seira responds by evading and using close range moves. She moves in on him and attacks, landing gashes and cutting off his mustache. She also receives a cut on her cheek. Frankenstein complements her once more.
Then Seira invites Rostere to attack her with his full powers as she herself draws out her Death Scythe. Seeing the changed aura of his opponent, Rostere transforms. Seira uses a spinning slash with her soul weapon. But Rostere manages to block Seira's Death Scythe and attacks with a power beam shot from his horn, Seira manages to evade. Meanwhile, Frankenstein defeats Muar and Rostere deems it'll be troublesome to face both him and Seira. However, Seira assures him that she will be the only opponent in this battle. So, Rostere becomes overconfident thinking he can beat Seira if she is fighting alone. Both attack each other with Rostere blocking all of Seira's attacks and Seira evading his. One of Rostere's attacks hits Seira and her sleeves get torn. Frankenstein assumes she is trying to gain battle experience and feeling. Just then, Rostere aims another power beam from his horn but Seira lets out an enigmatic smile. She spins her scythe and brings on the Grim Reaper. One massive blow of her gigantic Death Scythe slices the building and road into halves as well as landing a massive gash on Rostere. He cannot believe that he is being defeated by a "brat".
Seeing that he is completely losing to Seira, Rostere thinks of a getaway plan: hiding among normal humans so that nobles would not attack him there. As he suddenly jumps to flee, Raizel traps him with his Blood Field and stops him from getting away.