There are quite a few unlockable cpu opponents in Yu-Gi-Oh! 5D’s World Championship: Over the Nexus for the Nintendo DS.
Here is the full list of unlockable cpu opponents, and what you need to do to unlock them.
Archlord Kristya – Defeat Guardian Eatos three times
Blackwing, Zephyrus the Elite – Summon Blackwing, Silverwind the Ascendant
Bountiful Artemis – Defeat Deep Sea Diva three times
Dark Simorgh – Defeat Vylon Omega three times
Dragunity Arma Leyvaten – Achieve 666 total summons
Ehren, Lightsworn Monk – Summon Judgment Dragon
Elemental Hero The Shining – Summon Vylon Omega
Evil Hero Dark Gaia – Achieve 50 hours total play time
Gladiator Beast Gyzarus – Get 10 consecutive wins
Guardian Eatos – Achieve 100 hours of total play time
Infernity Doom Dragon – Win with Final Countdown’s effect
Junk Destroyer – Summon Shooting Star Dragon
Legendary Six Samurai, Shi En – Summon Gladiator Beast Heraklinos
Machina Fortress – Summon Odin, Father of the Aesir
Malefic Paradox Dragon – Summon Malefic Paradox Dragon
Master Hyperion – Defeat Tiki Curse three times
Meklord Emperor Granel Infinity – Defeat Earthbound Immortal Ccapac Apu three times
Power Tool Dragon – Defeat Wynnda, Priestess of Gusto three times
Queen Angel of Roses – Defeat Flamvell Baby three times
Red-Eyes Darkness Metal Dragon – Summon Red Nova Dragon
Stardust Dragon/Assault Mode – Defeat Great Maju Garzett three times
Thestalos the Firestorm Monarch – Collect 50% of all bonuses
Thunder King Rai-Oh – Defeat Gravekeeper’s Visionary three times
X-Saber Souza – Get 10,000 or more max damage
