Knight Percival is the evolution of Percival. He evolved after receiving the Darkus Attribute Energy from Exedra. Since his evolution, Percival looks even more like a knight and even has a sword and shield. Knight Percival wears a new cape split in two that protects him from fire and water and has additional horns on his head and shoulders for increased protection from attacks. The two dragon heads on his wrists have moved to his shoulders. He wears impenetrable armor protecting his arms and legs. He also carries a mammoth stainless steel sword to slay his adversaries. As Ace's Guardian; they work alongside Dan and Drago to protect New Vestroia with the Attribute Energy of Exedra. Knight Percival can fly on Flash Falcon Fly to reach greater heights.
In Saved By the Siren, he faced Macubass, Mylene's new Mechanical Bakugan. He managed to win the first round but was beaten in the second. Knight Percival would have lost, but was saved by Klaus von Hertzon and Sirenoid. With their help, Knight Percival defeated Macubass.
In Final Fury, he also fought Snapzoid, Lumitroid, Clawsaurus, and Farakspin (Digital Clones) in a place that looked like Bakugan Interspace. He later destroyed the Alternative with the combined efforts of himself, Master Ingram, Saint Nemus, and Helix Dragonoid.
- Ability Cards
- Black Out: Transfers 200 Gs from the opponent to Knight Percival.
- Stray Thunder: Adds 300 Gs to Knight Percival.
- Dainsleif (Thunder Sword/Dang Sleath): Adds 300 Gs to Knight Percival.
- Bind Shield (Blind Shield): Transfers 300 Gs from the opponent to Knight Percival.
- Giol Gunner: Adds 500 Gs to Knight Percival.
- Fusion Ability Cards
- Vermilion: Subtracts 200 Gs from the opponent.
- Deathly Curvier (Death Curvier/Mortal Curvier): Transfers 200 Gs from the opponent to Knight Percival.
In Japan, the Pyrus version in BST-10 comes with 500 Gs. The Subterra version in BST-10 comes with 540 Gs. The translucent Darkus version in BST-10 comes with 560 Gs. The Darkus version in BBT-04 comes with 520 Gs. The Aquos version in BST-10 comes with 520 Gs.
- During his first battle, he mistakenly introduced himself to Macubass as Darkus Midnight Percival.
- He was only referred to as Knight Percival and Midnight Percival once each in the dub, meaning that it is entirely possible that his name (in the dub) is Midnight Percival, due to the fact that Japanese names not being translated was common in the second half of New Vestroia.
- Strangely, he and Minx Elfin have the same pose on the Gauntlet.
- Currently, Knight Percival is the only evolved Bakugan that had one of his abilities become weaker in terms of G-Power effects. His original Darkus Thunder added 300 Gs to him and subtracted 200 Gs from the opponent. But his new ability, Stray Thunder (shown above) just adds 300 Gs to his G-Power.
- He is the first Bakugan to win a battle in Bakugan Interspace.