User blog comment:Koishi-Komeiji/Septem (Revisited)/@comment-4802891-20181106172512/@comment-24965192-20181107115230

That's a good plan to control Altera upon breaking her 2nd bar.

Yes, I intended the Flauros battle to be throwback to the Touta Challenge Quest in Gilfest. An epic NP bonanza! Though, we enough stacks, one can rack up to the millions of damage as you can get at least 1 50% NP damage up per turn, so 6 million HP isn't too much.

I believe it should be possible. It's simply buffing himself with what your Servant has. Though star per turn, critical star generation up, and critical star absorption up should translate into critical chance up for Romulus as he is an enemy.