If a monster(s) is Special Summoned, except from the Graveyard, while you control a Level 7 or 8 Dragon-Type monster: That face-up Special Summoned monster(s) has its effects negated until the end of this turn (even if this card leaves the field). Once per turn: You can send 1 other face-up card you control to the Graveyard; Special Summon 1 "Dragon Lord Token" (Dragon-Type/LIGHT/Level 1/ATK 0/DEF 0). If this card is in your Graveyard: You can send 1 Level 7 or 8 Dragon-Type monster from your hand or face-up from your field to the Graveyard; add this card to your hand.
Red-Eyes Slash Dragon is a good monster to have on the field with Ruins of the Dragon Lord. You can negate the effect of monsters your opponent special summons. And Red-Eyes Slash Dragon can provide you with cards to fuel the summoning of Dragon Tokens. Additionally, Red-Eyes Slash Dragon synergizes well with the Felgrand Archetype this card was made for.
Here are some monsters that you could use to synergize with this card.
|Actions||Sends from your field to your Graveyard / Activates from your Graveyard / Sends from your hand to your Graveyard / Adds from Graveyard to hand|
|Monster/Spell/Trap categories||Negates the effects of Effect Monsters|
|Summoning categories||Special Summons Tokens|