Yu☆Gi☆Oh! Arc-V

Synopsis

The last match for the first round of the Friendship Cup is between Shun and Dennis, both Lancers. Against Shun who suspects his identity, Dennis plays in his usual Entertainment style. However, when Shun forces him into a corner, Dennis suddenly Summons a new monster that surprises everyone!

Dennis draws "Antique Gear Chaos Fusion" and subsequently activates it. By sending "Fusion" from his hand to his Graveyard and selecting one "Antique Gear" Fusion Monster in his Extra Deck, he can banish monsters from his Graveyard that were Special Summoned from the Extra Deck equal to the number of the selected Fusion Monster’s Fusion Material monsters, and then Special Summon those Fusion Material Monsters from his Deck, Extra Deck or Graveyard with their effects negated, ignoring the Summoning conditions. Dennis banishes "Trapeze Magician" and all three copies of "Shadow Maker" from his Graveyard to Special Summon "Antique Gear Hound Dog" from his Deck and "Antique Gear Double Bite Hound Dog", "Antique Gear Triple Bite Hound Dog" and "Antique Gear Ultimate Hound Dog" from his Extra Deck. The effect of "Antique Gear Chaos Fusion" then sends the Special Summoned Fusion Materials to the Graveyard to Fusion Summon "Antique Gear Chaos Giant" in Attack Position.

This revealed that Dennis is working for Academia in Fusion Dimension!

(Source: Yu-Gi-Oh! Wikia, edited)