"Red-Eyes B. Dragon" + 1 Warrior monster
When a "Red-Eyes" monster declares an attack: You can target 1 Warrior monster in your GY; equip it to this card as an Equip Spell with this effect.
● The equipped monster gains 200 ATK. When a card or effect is activated that targets a card you control (Quick Effect): You can send 1 Equip Card you control to the GY; negate the activation, and if you do, destroy that card. If this card is destroyed by battle or card effect: You can Special Summon as many monsters from your GY as possible, that were equipped to this card.
|Pack||Resonance of Contrast [UR]|
The best way to get Red-Eyes Slash Dragon out is with Red-Eyes Fusion, which lets you use monsters from the deck as material. Using monsters from the deck as materials means you won't need prior set up and also won't spend any resources in making your boss monster. The materials you used can also be a way to pitch graveyard effects out of your deck, or pitch a monster you want to attach to Red-Eyes Slash Dragon.
One huge downside is you won't be able to summon anything else during the turn you use Red-Eyes Fusion. Unlike Neos Fusion you can't do your summons beforehand or you won't be allowed to use Red-Eyes Fusion. This means your entire board setup for the turn will only consist of Red-Eyes Slash Dragon and some backrow.
You can attach Black Metal Dragon from your hand to a Red-Eyes Slash Dragon and give it a 600 ATK boost. The Black Metal Dragon can then be used as cost for Red-Eyes Slash Dragon's targeting protection, which in turn lets you search any Red-Eyes card.
If you want to search a Red-Eyes Spell/Trap card, you can search Red-Eyes Insight first and then use it to search your intended card. This lets you further cycle your deck.
Red-Eyes Insight is a must for any Red-Eyes deck. It pitches a monster to the graveyard and searches for any other Red-Eyes Spell/Trap. This lets it combo well with Red-Eyes Spirit to revive the monster you just sent to the graveyard. You can also search Red-Eyes Fusion and make Red-Eyes Slash Dragon while further thinning your deck.