Diavolo’s birthday is one of the most family-friendly celebrations in the Devildom, at least by demon standards. There are still plenty of demons that don’t necessarily agree with his efforts to bring the three realms together peacefully, but the naysayers can’t resist the lure of extravagant parties that silence their doubts and criticism - if only for a short time.
Halloween traditions from the human world amuse and amaze Diavolo and he vows each year to embrace them as part of his birthday celebration. The added bonus, if only a subtle one, is that the Devildom’s most deadly destructive mischievous demons have something else to keep them busy so that the human world can celebrate their version of Halloween with less chaos and bloodshed. Usually.
(The number of unsanctioned hauntings, accidental summonings, and demon-related deaths have steadily decreased in recent years.)
The Demon’s Lord Castle is decorated top-to-bottom in time for a legion of demon children visit in costumes, all of them hoping to trick and treat their way through the palace. The Little Ds enjoy dressing up too - or maybe it’s just an excuse to throw toilet paper all over the place (and each other) and pretend they’re dressed as mummies for the day. Lucky guests can spot Barbatos sporting some elaborate costume of his own design while handing out poison apple cider and warm cookies fresh from the oven. If you follow the echoes of delighted laughter, you’ll eventually stumble on the prince himself, weighed down by little demons hanging off his back and from each limb, dressed as a vampire lord wearing an impractical cape and his face painted with fake (?) blood.
(Diavolo’s costume inspiration is something he saw in a human world film once, but the threat of blood-sucking doesn’t scare demons nearly as much as it does humans. Even the youngest demons only giggle at the prince’s strange antics, not at all frightened by his elongated fangs. His lips and chin might be stained red for dramatic effect, but his sharp teeth and even sharper claws are very real.)
Later on Halloween night, Diavolo’s staunchest supporters gather in the lavish ballroom for a night of fine food, music, and dancing. It’s a rare occasion that demonic offspring, such as Mephisto’s kid brother, are invited to attend as well. Mephisto is teary-eyed at his lord’s most gracious gesture, so much that he doesn’t realize his family is seated at a table close to the residents of Purgatory Hall. Mephisto and Simeon are unofficial babysitters for Luke and the other underage guests for the night, even if they don’t know it yet. Any complaints are half-hearted at best and as far as babysitting goes, this isn’t a terrible hardship either. The young ones are kept busy with small gifts and served dishes made specially for their picky tastes. Bottles of sparkling juice, similar in appearance and but sweeter than real Demonus, are passed around and poured into plastic wine goblets. Little luxuries for little demon lords (and little angels-in-training).
When Luke and the demon children inevitably disappear at some point during the party, it doesn’t take long for their concerned chaperones to find them passed out underneath one of the tables in a cuddle pile of costumes and candy, exhausted from an entire day of excitement and far too much sugar.
