“By the Lead of Fragile Chain, I'm Existing Here——
I am Nightmare, I am Grendel Biting Myself...!!”
— Transformation lines
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 "/////?////".
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 Prologue: "Spriggan of Downtown" (旧市街の
Two forms of Grendel, Grendel-Alter and Grendel-Sin, are used in Chapter 5: "White Night Carnival" (白夜のカルナヴァル) and Finale: "For Your Return Someday" いつか還る貴方のために.
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.
- 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".