Damien is struggling with coming to terms with being the antichrist just as Merlin stumbles back into the life of the reincarnated Arthur Pendragon. Damien doesn't remember that other life in Camelot, but is drawn to Merlin all the same. Merlin is ecstatic to have his king back, but is also confused and conflicted by what their ultimate destiny might entail this time around. Bonus points if Merlin hates Ann Rutledge on sight and there's a big showdown between the two because they both think of Damien as theirs.
Damien, Damien/Merlin