Substitute for blood?
Depending on the animal, blood would impart a somewhat metallic taste and a certain “richness” - not really the umami-meatiness of red meat, more like the earthiness of liver - with a slight sweetness. 

The flavor profile will be quite different depending on the animal, with pork being more neutral than the more intense and metallic beef.

A substitute would depend on the recipe. But the acidity of red wine is very much not what blood would contribute to a dish. If the binding properties are to be ignored, think “beets plus sautéed mushrooms”, as a very, very vague flavor approximation. But if your sauce is rich per se, you can probably just skip the blood without doing much culinary harm.