Seiran is the cute junior every girl fan girls over, but he hides a very dark secret other than the fact he's a rose knight.
Although he appears cute and innocent, Seiran does have his dark side as seen with the race between Kaede and Haruto when he gave Kaede some medicine. In quote Kaede shouted, "Jesus Christ, I just saw hell!" after returning with Seiran.
Also, Seiran has a streak for messing up what he's saying since he's used to talking to girls being around guys makes him mess up and talk like he would to girls then he corrects himself as if he never said anything. He lives with his Grandma in a secluded mansion surrounded by flowers (roses to be exact) which Seiran is allergic to but he thinks its just a cold he always has. His dream in life is to create a natural blue rose.
We know little about Seiran except that he's the artificial rose; the one who is to be sacrificed for peace. Even though Anis refuses to believe that Seiran accepts wholly; after all that's why he was created.