What started as finding a character-specific tech trap turned into an all-out study. I will share my research notes.
The move in question is GDR, BT B+K, 6A+B. There are two versions of this. One where the enemy slides away from you after the BT B+K, and the other where they fall directly at Cervantes' feet. Here are my results:
Aeon, Siegfried: At range, tech trap BF. At Cervantes' feet, tech trap BFL
Natsu, Tira: At range, tech trap BF. At Cervantes' feet, tech trap BFLR
Nightmare: Regardless of range, tech trap BFL
Astaroth: At range, tech trap BFL. At Cervantes' feet, tech trap BFLR
All other standard characters + Algol: Regardless of range, tech trap BF
Kilik(tested multiple styles), Edge Master(tested Mitsu style), Elysium(tested all styles): [ditto]
Dampierre: Unable to test
NOTES: After testing back and forward tech roll against characters like Pyrrha and Viola and connecting, I decided to not bother testing back and forward rolls on everyone, believing this lunging forward stab move would always catch those movements. After catching them with 6A+B, a CE is guaranteed.
Hopefully this study will help understand which characters may stand out among character-specific tech traps. Other than that, it's pretty much just data. Only bits of it are practical in a match.