Blunder, also called Fault in Guilty Gear Isuka, is one of A.B.A's Special Attacks, first appearing in Guilty Gear Isuka.
Overview[]
In Guilty Gear Isuka, A.B.A climbs up Paracelsus and flips over, using both legs to kick down a stream of (what seems to be) blood down to the floor. She tumbles however and lands on her butt while using the chain she holds onto to get back on her feet.
In later games as of Slash, A.B.A climbs up Paracelsus and flips over, double-toe-kicking through a bubble-shaped projectile in the form a brief-glossed spike image before landing on her knees away from them, then getting back up.
Both versions can inflict stagger upon an opponent that attempts to block due to acting as a guard crush/break that cannot inflict any direct damage this way (thus only inflicts chip damage if blocked like so), though the original Isuka variant could be blocked low normally and the perks of Sacrifice Mode causes A.B.A. to lose HP even if the move is blocked either standing or crouching.
In Slash onwards, it hits overhead as it can no longer be blocked low while also no longer inflicting self-damage on A.B.A through Sacrifice Mode's HP drain even if blocked. Even then, all variants can be normally air blocked with no consequence other than chip damage to the defender.
Originally inflicted (anywhere) wall bounce in both Isuka and XX Slash on hit, but inflicts ground bounce instead in the Accent Core games.
This can also be done after the Ruin followup for Deletion as 
+ 
, but only on hit or block for the first 2 multi-inputs and only possible in the Accent Core games.
Details[]
To be added...