Man, this is such a weirdly specific thing I love about vampire lore. It's never just one neat package, which is part of the fun. The powers from being marked—bitten, claimed, whatever you want to call it—seem to depend entirely on what the author needs for the plot and the kind of relationship they're building.
Some stories treat it like a slow-drip supernatural infection. You might get heightened senses first, maybe a craving for rare meat, a sudden aversion to sunlight that's more like a bad migraine than bursting into flames. Your strength and healing tick up a notch. It's a messy, confusing transition period that's great for character angst, making the human character feel like they're losing themselves piece by piece. Think of Elena in 'The Vampire Diaries' books and show, navigating that grey area before turning.
Then you've got the stories where the mark is less about pre-vampire powers and more about a psychic or emotional tether. That's the real meat of it for a lot of romance subgenres. The marked human might start dreaming the vampire's memories, feel their emotions from miles away, or get a low-grade version of their sire's specific gift, like influencing thoughts or sensing lies. It creates this forced intimacy, which can be horrifying in a darker tale or the foundation of a fated-mate bond in a paranormal romance. In J.R. Ward's Black Dagger Brotherhood, the whole sympath bond starts with a marking that links the souls, way before any turning happens.
And let's not forget the downside, the flip side of the coin that a lot of lighter stories gloss over. That mark can be a beacon. It might draw the attention of the sire's enemies, make you taste 'different' to other vampires, or tie your life force to theirs so if they die, you fade away too. The power isn't always a gift; sometimes it's a brand that makes you property or a target, which is honestly more interesting to read about.