Staring at Wallington Hall and imagining AUs where Nea/Mana never went missing, and has Allen attend their lavish Campbell Mansion parties and Kanda (who isn't a known Order Exorcist outside of E.Asia) comes investigate undercover.
Kanda approaches him to investigate this mysterious 'host', as he heard one of the Noah's men manifested Innocence that saved him when he should be dead... and Kanda was tasked with Link (in disguise) to find out if this 'host' is the heart...
They fear the worst should the heart fall into the Noahs' hands.
Kanda closes in on Allen during the dances and fishes information out of him. Half the floor is after Kanda because of the way he looks, but he's staunchly ignoring them and Allen doesn't know why.
That Kanda is clearly approaching him with intention does not stop him from stomping Kanda's feet when Kanda is being rude, lol. Kanda's asking all about him. Of course, Kanda is fishing information out of him.
Allen's sad, kind smile enamours him when he talks about himself, and his beloved 'twins' that took him in.
Allen's masks also kind of irritate him. So he purposely barbs the real Allen out of there, smirking in victory as he asks
"Oh-? Is that what you're really like?"
And Allen flushes when he realizes Kanda was trying to get to the real him.
Kanda sees him trying to pretend to eat properly, then try to sneakily black hole some food off the party tables. Kanda teases him for it and they bicker-flirt the whole party.