Sauria and Dart from my webcomic would definitely celebrate Christmas however their experiences would be dramatically different. Sauria pre-leaving would've been spoiled on many Christmas activities. Dart experienced the bare minimal from his parents of receiving socks as gifts and watch a single Christmas movie on repeat on TV.
The demons in my webcomic definitely have their own holiday which I haven't fleshed out yet. My only note is that it would have a focus on charity/sharing resources which is the only time the Hell Kingdom bothers to do anything for the community.
Anyways here's my webcomic:

Hybrid: Humanity
Genre: Fantasy / Action
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Description: In the 1800s, an unprecedented convergence of demons and humanity altered the course of history, sowing the seeds of conflict and camaraderie. Now, in the world of the 2100s, a traumatized half-demon teenager is drawn into a realm teeming with covert battles and concealed truths.
Within this intricate tapestry of magic and mystery, ancient pools of power house unrevealed potentials, ready to ignite. Accompany our enigmatic protagonist as she journeys through a world where allegiances flicker like shadows, and the distinction between friend and foe remains perpetually uncertain.