Let's see, the obvious one is 'Knight of the Empyrean', but honestly, I dropped it after a hundred chapters. The art's gorgeous and the whole vampire nobility thing is cool, but the romance got too... circular for me? Like, they'd have a big moment, then some external drama would reset their relationship progress. I found myself way more into the side characters. 'The Blood of Madam Giselle' is another that pops up a lot; it's definitely heavy on both romance and supernatural politics, though it leans more mature. The drama there feels more baked into the world-building, less like arbitrary obstacles.
Honestly, for a real blend, I keep going back to older stuff like 'Noblesse'. Rai and Frankenstein's dynamic is the core for me, even if it's not traditionally romantic. The supernatural drama scale is huge. Maybe it's cheating because it's not a straight romance, but the emotional bonds carry a similar weight.