@Eriko Yes! It was noted by Seo Dawon that Lee Kyung (or Yikyung going by the manhua spelling) probably mumbles to himself because he must live a lonely life. The implication is he has no friends so he got used to being alone/mumbling to himself.
@Necromancer Ohhh !!! Thanks for that ..i was kinda confused.. And thanks for the spoilers too lol .. Tho can u tell me who was Han Kiseok ...i am sry i am bad with names i forgot ...(╥﹏╥)