Incursio Move Andernach

Incursio Move Andernach, also known as the Red Dragon Emperor's Three-Ponged Promotion and Invasion, is a specialized technique used by Arthur Pendragon that changes his Scale Mail armor into three different forms based on the Evil Pieces system.

Summary
In Volume 6, one of the Seven Great Satans, Myrddin Beelzebub, creator of the Evil Pieces system, remodels Arthur's King/Master Evil Piece and gifts him with three Transfer Pawns, after he learned that the original program written by him was overwritten by a different code, which he speculates to be the effects of the Juggernaut Drive, remodeling it to adapt to the power of the Red Dragon Emperor.

In Volume 7, Arthur meets two of the previous holders of the Boosted Pump inside his subconscious. One of the past holders, Elsha Scarlet, then gives a box to Arthur which she claims is one of Arthur's future possibilities. During the battle with the Hero Faction in Kyoto in Volume 9, in an attempt to rescue Kunou's mother Yasaka, Arthur manages to awaken his new powers which allows him to use the Three Transfer Pieces and still contain his position as King/Master,and changes his Scale Mail armor to different forms based on the Rook, Bishop and Knight Pieces. He then uses this ability during his fight with Cao Cao, who comments the three new forms of Arthur's Scale Mail as "Andernach Moves", which are illegal moves outside the Evil Pieces system. After Ddraig compares the three forms to a "Triaina Invasion" also known as an Incursio, Arthur then decided to name his new ability "Incursio Move Andernach".

Abilities
Incursio Move Andernach has the ability to change Arthur's Scale Mail armor into three different forms based on the Evil Pieces system, each with their own strengths and weaknesses. It also allows Arthur to Demote his King/Master Piece into a Rook, Bishop of Knight, through the use of his three Transfer Pieces.

Welsh Incursio Sonic Knight
Welsh Incursio Sonic Knight, also known as the Dragon Invasion Star Knight, is Scale Mail's Knight form. In this form, Arthur possesses enormous speed (Godspeed as he called it), but to make full use of it, Arthur must shed his excess armor, causing it to become thin to the point where it has low defense, making him vulnerable to powerful attacks.

To change into Welsh Incursio Sonic Knight, Arthur shouts the form's name, in which he gains an increase in speed. He then shouts "Armor Purge!" causing all but the absolute minimum armor required to fly to be shed in order to reduce weight and drag, further increasing speed. The armor then morphs into a more aerodynamic form, after which the Greater Boost announces  "Change Sonic Liberty!"

Welsh Incursio Panzer Rook
Welsh Incursio Panzer Rook, also known as the Shaking German Dragon Tank, is Scale Mail's Rook form. In this form, Arthur possesses massive power and defense but has a low body maneuvering speed because of the massive, thickened armor. Its finishing move is Rigid Impact (リジッドインパクト, Rijiddo Inpakuto), a punch that has its power and speed increased by nailing the percussion hammer located at his elbow.

To change into Welsh Incursio Panzer Rook, Arthur shouts the form's name, after which the Greater Boost announces "Change Rigid Panzer!"

Welsh Incursio Alamos Bishop
Welsh Incursio Alamos Bishop, also known as the Dragon Avalon Monk, is Scale Mail's Bishop form. In this form, Arthur possesses an enormous amount of magical energy, which he applies to the two cannons at the back of his armor. Its finishing move is Avalon Blaster (アバロンブラスター, Abaron Burasutā), a severely boosted equivalent of his Dragon Shot capable of leveling battlefields and briefly warping space-time. The drawbacks to this is the amount of time it takes to charge the cannons and stamina lost with each shot.

To change into Welsh Incursio Alamos Bishop, Arthur shouts the form's name, after which the Greater Boost announces "Change Avalon Alamos!"

Trivia

 * Incursio is Latin for "Invasion."
 * This technique is named after a variant of chess of the same name
 * Welsh Incursio Alamos Bishop is modeled after the Gundam Double X, the titular Gundam from After War Gundam X.
 * The first form of Welsh Incursio Sonic Knight is modeled after Wild Würger from Namco Bandai's Super Robot Wars'  series of video games, under Banpresto's Project ATX line of characters. The second form of Welsh Incursio Sonic Knight modeled after the titular character in Kamen Rider Kabuto, the 16th installment of Toei's Kamen Rider Series. The two-stage transformation (Knight's first stage being its "Masked" Form and the second being its "Rider" Form) is also a reference to Kabuto's "Cast Off" function on their Masked Rider System.
 * Welsh Incursio Panzer Rook is modeled after the titular mecha from Sunrise's anime series The Big O. Also, its finishing attack, "Rigid Impact", is named after Big O's signature weapon, "Sudden Impact".
 * Unleashing the power of Incursio Move Andernach has seemingly caused Arthur's King/Master Piece to become a Mutation Piece, with it being of high value. Cardinal Crimson Incursio transformed his three Transfer Pieces into Mutation-Transfer Pieces.