Dragon Master Knight is a fusion of Blue-Eyes Ultimate Dragon and Black Luster Soldier from Yu-Gi-Oh! franchise.
In some episodes of the dub, this card is mentioned by its Japanese name: Master of Dragon Soldier. In the original, this monster's attack was called "Galaxy Crusher", while in the dub, its attack is called "Dragon Saber Blast".
In episode 45, Yami Yugi and Seto Kaiba use this card during the battle against the Mythic Dragon. Yami Yugi summons this card via "Polymerization". As there were 8 Dragons on the field and Graveyard, this card gained 4000 ATK. This card then attacks and destroys "Mythic Dragon", winning Yami Yugi and Kaiba the battle.In this arc, it gained 500 ATK points for every Dragon-Type monster on the field and in the Graveyard. It also had only 4000 DEF points.
In episode 98, this card appears in a flashback Kaiba has when he recognizes the Big Five as the same people who trapped him in his own virtual reality game.
In episode 113, this card appears in a flashback Leichter has when he remembers Yugi using this card to defeat "Five-Headed Dragon" as the final move in the battle between Yugi and his allies and the Big Five after Yugi states that they defeated "Five-Headed Dragon" before. Leichter then claims that even though this card was able to defeat "Five-Headed Dragon" last time, Yugi can't do the same thing again as he doesn't have the proper cards necessary to summon it.
Waking the Dragons
In episode 177, Yami Yugi uses this card during his Tag Duel with Kaiba against Dartz. He summons this card via "Polymerization". Yami Yugi then activates "Meteorain" to allow this card to inflict piercing damage this turn. This card then attacks and destroys Dartz's "Orichalcos Gigas" (who was in Defense Position), but Dartz uses the effect of "Orichalcos Kyutora" to nullify the damage he would taken. In the next episode, "Orichalcos Gigas" attacks this card. This card then destroys "Orichalcos Gigas", but the effect of "Orichalcos Kyutora" nullifies the damage that Dartz would have taken. Dartz then uses the effect of "Orichalcos Gigas" to revive it and make it stronger. Later Kaiba activates "Reflect Energy" to allow this card to attack Dartz directly this turn. This card then attacks Dartz directly, but Dartz activates the effect of "Orichalcos Deuteros" to Tribute "Orichalcos Gigas" and destroy this card. Yami Yugi then activates "De-Fusion" to return this card to the Extra Deck and Special Summon "Blue-Eyes Ultimate Dragon" and "Black Luster Soldier" from the Graveyard.
Dawn of the Duel
In episode 200, this card appears within Kaiba's briefcase when he opens it up and takes his Duel Disk with him.
In episode 218, Pharaoh Atem (who had fused together with his "Black Luster Soldier") fused with Seto's "Blue-Eyes Ultimate Dragon" in order to create Dragon Master Knight. He then fought Zorc. While Zorc managed to defeat the creature, it took a great effort for him to do so as he was injured in the process.