Myeongdal is a damage-boosting support operator that seals enemies and provides exceptional ATK% and ASPD% boosts at the cost of sealing all your allies’ skills. His buffs are good, but the extremely awkward proc order makes it hard to put him into practical use. 

At the time of writing, his main use case lies in his synergy with Swan Claire. When affected by Skill Seal, Swan attacks with her powerful enhanced attacks that reach deeply into the enemy backline and deal massive damage. Unfortunately, Swan’s Ultimate Skill applies Skill Seal immunity to herself and allies within range, removing Myeongdal’s effect. Still, the sheer damage output of this gimmick setup is so high that it can win games.