You can only activate this card during the Damage Step of the Battle Phase that a Fiend-Type monster on your side of the field attacks or is attacked. Pay Life Points (in multiples of 100 points) to decrease 1 of your opponent's monster''s ATK and DEF by the same amount of points until the End Phase of that turn.
![Bark of Dark Ruler [LOD-010] Common | RetroPlay Games](http://shop.retroplaygames.com/cdn/shop/products/07e8ec76-5853-5d6b-bf35-1dbcbf513fb8_90225a10-293d-4874-92f6-bb7f69d26a37.jpg?v=1702648946)
