Grendel

Grendel is the mysterious Nightmare-Clad form Van Arkride takes when his Xipha's Holow Core Mare materializes into reality under influence of the Genesis (Blue) that acts as a medium for "/////?////".

Appearance
It is currently unknown whether Grendel is just an armor or a creature with its own will. The transformation is described as Van's body being "covered in his nightmare", giving a slightly larger armored body than usual.

Grendel is first manifested under the intersections of Van Arkride, his Xipha's Mare and Agnes Claudel's great-grandfather's last invention: one of the Oct-Genesis during.

Two forms of Grendel, Grendel-Alter and Grendel-Sin, are used in and.

Gameplay
Van Arkride can "clad" into Grendel for certain storyline battles, The transformation significantly boosts various stats and makes Van capable of attacking with close-combat twice in quick succession and combining Crafts. Additionally, using one S-Boost slot will grant him another turn, thus making him able to perform a total of three actions in a single turn.

Grendel's S-Craft is Regal Strike.

With the battle against Vagrants-Zion, Van Arkride can Nightmare-Clad the Grendel form through the Craft: Take the Grendel.

Trivia

 * Grendel is the name of a character in the Anglo-Saxon epic poem Beowulf, described as "a creature of darkness, exiled from happiness and accursed of God, the destroyer and devourer of our human kind".