[There is rarely a singular reason to pay another person a compliment. He wonders how far he can press her on the topic.]

I take it you had some personal connection to the form the foe chose to take, madam?

[Celestia shouting 'You are not my sister' and Luna attacking with wild abandon had been telling, after all.]

A connection to do with your moon, perhaps?

[It's natural for him like this, easier, to turn the discussion around and test the boundaries of what she will allow rather than dwell on his own frailties.]