After the more cartoony and simple presentation of Slay the Spire (the most famous and probably well-regarded of card battle games), the distinctive aesthetic of Deck of Ashes immediately drew me in.
Hand-drawn, Lovecraftian creatures abound. Ghoulish witches and genuinely unsettling undead creatures litter the battlefield, and I am all in favour of it.
On top of this, the battles themselves are brought to life by creepy animations (the jester character sprouts monstrous claws from his back when he attacks) and a suitably gothic soundtrack.