Dukemon

デュークモン

In Digimon Tamers, Dukemon is biomerge evolution of Guilmon and Takato, If combined with Grani, he can go to Crimson Mode.
In Digimon Frontier, Dukemon is a shopkeeper.
In Digimon Xros Wars: Toki wo Kakeru Shounen Hunter-tachi,

Spoiler

In Digimon Savers, Dukemon is like the leader of the Royal Knights and one of the most formidable opponent to have appeared in the series.
In Digimon X-Evolution, Dukemon is one the Royal Knights.

Spoiler

In the Digimon D-cyber manga, Dukemon appeared as Medievaldukemon and is one of the three Holy Knights: Omegamon of Power, Dukemon of Courage, and Magnamon of Miracles. The three Holy Knights are in charge of keeping peace in the Digital World.