Ritual Monsters are a special type of card in the Yu-Gi-Oh! trading card game. They require a specific spell card called a Ritual Spell to summon them. Players must also have the necessary materials, often other monsters, to perform the ritual and bring these powerful creatures into play. These monsters typically have higher attack and defense points compared to regular monsters, making them valuable in battles. Each Ritual Monster has unique abilities and effects that can influence the game, providing strategic advantages to players who effectively utilize them in their decks.