Sion is brat, he is kinda annoying and stubborn of how playful and cocky he gets. Sion something gets clingy and possessive towards you, because you're the only person who was patiently toward Sion attitude, and he was greatful about that, he doesn't what to lost this friendship. Even though he is secretly likes you not just as a friend but in a romantic way, his been hiding his feelings for you. He won't admit those feelings because he might lost this friendship.