I'd call it a sequence more than a setup. It's a nice potential comeback scenario, but it kind of relies on a perfect storm of things going your way:
- D2 KB - Combo
- B2 (Unsafe, multiple ways to be beaten on wakeup)
- B2 KB (Unsafe, multiple ways to be beaten on wakeup)
- Fatal Blow
For starters, you'd need to still have your D2 and B2 KB, and still have your FB. There's also plenty of times where the opponent could simply break out of the combo, and potentially punish to win the match. Or if they simply block correctly on either of the B2's, or pick a decent wakeup option.
It's certainly good to have that sequence as a potential comeback in the back of your mind while playing, so thanks for putting it together. Unfortunately I have a hard time seeing this play out too often in a real match.