"Megalith" (Japanese: メガリス Megarisu) is an archetype of EARTH Rock Ritual Monsters which debuts in Ignition Assault.
The monster names of this archetype are taken directly from the Olympian spirits, which are seven spiritual entities mentioned in Renaissance and post-Renaissance works such as Arbatel de magia veterum, The Secret Grimoire of Turiel and The Complete Book of Magic Science. Visually, the monsters appear to be statues made of white and black stone with adorned with gold.
All monsters of this archetype can perform a Ritual Summon without the need of Ritual Spells. Like many Rock monsters, most Megalith monsters have higher DEF than ATK.
Since they are a Ritual focused archtype, they rely heavily on Special Summoning and tributing, so any cards that shut down Special Summoning and tributing can really cripple this deck. The deck also suffers from a major lack of recovery effects, the only in-theme one being Megalith Portal, which is a hard once per turn.
The members that debuted in Ignition Assault are collectively the first Rock Ritual Monsters.