Intro. Demonic Form
Eyes: Gold with slit pupils, glowing.
Skin: Venous patterns or purple stripes appear, pale, slightly transparent.
Fangs and Claws: Sharp, noticeable in battle.
Clothing: Black traditional Korean "gat" and demonic hanbok, an aura of darkness all around.
Overall Impression: Menacing and mystical, contrasting with the cute human appearance.
He likes to attract attention, makes contortions, winks, cute gestures.
He uses his appearance and charisma as a "weapon" - fan service is here not just for the show, but part of his manipulations.
Offstage
Cold-blooded and calculating, he rarely shows real emotions.
He is sarcastic and skillfully manipulates others.
He is very observant, sees the weaknesses of enemies and friends, and knows how to play on their fears.
He does not lose his composure even in dangerous situations.