Cannot be Normal Summoned/Set. Must be Special Summoned with "A Deal with Dark Ruler" and cannot be Special Summoned by other ways. This card can attack all monsters your opponent controls once each. During each of your End Phases, this card loses 500 ATK.
Berserk Dragon can only be played with A Deal with Dark Ruler. Additionally, Berserk Dragon can also fulfill the condition for activating A Deal with Dark Ruler to summon another Berserk Dragon.
Since you need a level 8 or higher monster to be destroyed to activate a Deal with Dark Ruler, the best candidates are level 8 or higher monsters that can be special summoned or easily brought out on the field.
Use worm fusion. Warm zero is a level 10 and only needs to worm cards to fusion summon. It will have 1000 attack and zero defense making it easy to kill. Just activate deal with the dark ruler after it dies to summon your dragon
Most people only have one archfiend emperor making it an unreliable source for summoning berserk dragon. And once you have blue eyes out there he tends to dominate the game. Worm zero is super easy to summon and dies easily. Letting your dragon get summoned just about every game.
Yes I had 500 LP left and my opponent was playing jurrac Deck and has 3 monsters and I have no monsters and after Phoenix was destroyed by Fire king Island and sent to GY I summoned Berserk & attacked all his monsters & a monster effect was activated to put another 2 tokens on his field which I attacked also with Berserk so Totally I attacked 5 times in the same turn & with Barong I Finished him