nachtwal

The materialisation of the Defense Program of the Book of Darkness.
Although the name was first mentioned in The MOVIE 2nd A's, for convenience, also can used here for the "Darkness of the Book of Darkness" in A's TV version.

Nachtwal's Forms

• Autonomous Form (基本形)

Multiple purple snakes.

• Equipment Form (装備状態)

An equipment with chain at Reinforce's left wrist.

• Armament Form (武装化状態/武装形態)

An arm mounted pile bunker known as Spear Cannon (槍射砲).

• Eroded Form: Darkness of the Book of Darkness (浸食暴走体/闇の書の闇)

The final boss in A's and The MOVIE 2nd A's.