This is another job for the creatuanary - Bloodsucker Dragon! I made him a mouth like a leech, but opening like a carnivorous plant or even like a bloody starfish. In addition, he has a special tongue designed to ... siphon off his food. On the side of the head and on the throat, I have placed special bags that fill with blood like the body of a blood-sucking insect.
The dragon itself is thin, pale, and its wings at the folds are equipped not with a pair of claws, but with snapping paws to hold its victims.