Awaken the Sky Tyrant [Commander 2015] SM225 You can only Special Summon

You can only Special Summon "White Steed of the Floral Knights" once per turn this way

Set: Legendary Collection 5D's Card type: Synchro/Effect Monster Rarity: Super Rare Attack: 3500 Defense: 3000 2 Tuners +" Red Dragon Archfiend" This card gains 500 ATK for each Tuner monster in your Graveyard

Those creatures have "This creature's power and toughness are each equal to the number of creature cards in its controller's graveyard

Ragavan enters the battlefield tapped and attacking

Awaken the Sky Tyrant [Commander 2015] SM225 You can only Special SummonSet: Commander 2015 Type: Enchantment Rarity: Rare Cost: {3}{R} When a source an opponent controls deals damage to you, sacrifice Awaken the Sky Tyrant. If you do, create a 5 5 red Dragon creature token with flying.