This is a new feeling, pride in someone else. Unfortunately, it is overshadowed by all this unyielding rage! -- Vegeta
Honestly, it never fails. Spend the better part of a lifetime building up an empire of power only to witness some snot-nosed kid hero gather up a band of five total snot-nosed kid heroes and thereby overthrow you in a heroic example of the power of friendship. The Dark Lord Mephis had attempted to circumvent all of this by seducing every possible foretold bearer of the next great hero and being the father of that particular child of his inevitable doom.
There was always a good opportunity for an "I am your father" reveal to throw the prospective hero off his game. There was also a risk of the hero foretold coming back from an assumed certain doom but so far... so good.
Until today. Today was... not going according to script. For a start, the entire misbegotten team was the Dark Lord Mephis' progeny. The big reveal wasn't all that revealing, given the Dark Lord's proclivities over the past couple of decades or so.