Top 3 in the famlily of the Greymons is...
VictoryGreymon
http://digimon.wikia.../VictoryGreymon
VictoryGreymon is a Dragon Man Digimon whose name and design are derived from "Victory Greymon". A subspecies of WarGreymon, whose body is clad in armor of the super-metal "Chrome Digizoid", it easily wields its gigantic crushing sword "Dramon Breaker", and is the "Dragon Warrior of Heroes" that fights against its opponents with unique sword techniques. In addition, VictoryGreymon possesses an evolutionary code that differs from Digimon that were naturally born in the Digital World, and it is thought that it is a Digimon that digivolved from a Digi-Egg that was produced due to artificial data intervention.[3]
This digimon could be one the most powerful digital Monsters by being a god, but the fandom got confuse by the VictoryGreymon of the Manga named Digimon Next because in that story he was another type of Victory Greymon, so it just another normal member of the family of the Greymon.
Still VictoryGreymon is most powerful than top 5 and 4. His amour and sword are made Chrome Digizoid hardest metal of the Digiworld, so if the Sword of K. Greymon hits V. Greymon's, Kaiser Greymon sword will break. Not just that Victory Greymon has an attack call Victory Charge that reflects the opponent's attack.