The Nova Monsters are a new type of Monster Card that are color-coded scarlet. Like the Normal, Effect, and Ritual Monsters, they are stored in the Main Deck. So far, they are the only monsters to be Special Summoned through a specific Special Summon (Nova Summon).
They appear to be another form of evolution of the Synchro Monsters. This is because they require Synchro Monsters to be sent to the Graveyard in order for their summoning to happen. Their names are also treated as their Synchro Counterparts' names, and their Ranks usually match their counterparts' Levels. For example: the Rank of "Scrap Nova Dragon", being 8, is the same as the Level of " ", also being 8. "Scrap Nova Dragon's" name is also treated as "Scrap Dragon". They also have the same respective Attribute, Type, ATK, and DEF of their Synchro counterparts.
The effect in which their names are treated as their Synchro counterparts count towards the Maximum of 3 Rule. For example, if you have 3 "Scrap Dragons" that are Synchro Monsters in your Extra Deck, you cannot have "Scrap Nova Dragon" in the same deck, because its name is always treated as "Scrap Dragon".