VelvetThis wasn't from the winning run, but it was one that got her down to 20% on the last HP bar.
The sequence of events here is just... 
(Infernal BBQ + turbo, elite, aggressive, potion scaling, no other modifiers)
Uploaded the two boss clears from today~
Ribauld: https://www.youtube.com/watch?v=OtSGNpnMhFQ
Ribauld
Barados defeated~
https://www.youtube.com/watch?v=lsudxkjhHYs
And this is the video of him bugging out 
(I was still learning the fight when it happened, so I only started recording halfway.)
Tevi - Barados (Infernal BBQ + Turbo, Aggro, Elite, Scaling)
TEVI - Katu in Chapter 1 (Infernal BBQ + Turbo, Elite, Aggro, Scaling)
And the last of the trio~
https://www.youtube.com/watch?v=HnGfBJTnttg
Just one more boss and I can finally leave chapter 1 
I know I set out to do this, knowing it would be unreasonable, but it's still kinda surprising to me that all three bosses were doable in the end 
Bird Nest