Use Cards to discard for it's effect, which has effects in the Graveyard or can be recycled. For example "The Black Stone of Legend" or "Master with Eyes of Blue". "Master with Eyes of Blue" can be used do destroy this card from the Graveyard when it Special Summons a Blue-Eyes monster. Causing this card to activate and summon another dragon.
The effect of "Chaos Emperor Dragon - Envoy of the End" can be used to send every card on the field and both players hands to the Graveyard, including this card, then this card can be used to immediately Special Summon "Chaos Emperor Dragon", or any other eligible target, giving you a tremendous advantage over your opponent since they will only have one card in their hand while you still have two powerful monsters.
Level 5 or higher DARKDragon-Type monsters that can be Special Summoned: