There’s always someone who ruins everyone else’s fun.

RD/KP06-JP020 和平の刺者 Wahei no Shisha (Betrayer of Peace)
Level 4 LIGHT Warrior-Type Effect Monster
ATK 1200
DEF 1000
[Requirement] None
[Effect] Choose 1 Attack Position monster (Warrior-Type) on the field and change it to face-up Defense Position.

Note: Yes, this card seems to be referencing “Messenger of Peace”

Source