Riding Dragon Kaiser Vermillion seems to be mandatory in the deck with The Blood.
V-SS09/038 RRR サンダーヴァレット・ドラゴン Thundervullet Dragon
Grade 1 / Normal Unit / Dragon Empire – Narukami – Thunder Dragon
AUTO (VC/RC) When placed, look at five cards from the top of your deck, reveal up to one “Dragonic Kaiser Vermillion” or “Spark Arrow Dragon” from among them and put it into your hand, shuffle your deck, and if you put a card into your hand, discard a card.
AUTO (RC) When your vanguard’s attack hits, this unit gets Power+5000.