'I've… made a terrible mistake.'
In hindsight, Sunny should have known that he was digging his own grave. It was just that he did not see Effie often these days, and so, he had forgotten…
That Effie's corrupting influence was just as terrible as the Corruption of the Void itself.
No, was it even more terrible?
In any case, the opportunities to stump the boisterous huntress were too rare! He simply could not pass on the chance to fluster her. More importantly… while Sunny knew that Nephis and Effie were close, Master Sunless had no way of knowing that. So, based on what he was supposed to know, the correct course of action had to be furthering the agreed-upon deception.
Therefore, Sunny passed the wine to Nephis.
And then took her hand.
Why did he do that?
Well, simply put… because he could.