As a follow up on that request which mirrors mine own earlier seeing as how you haven't done anything on that front, creating organic matter out of change magic as using one's own Mana; extracting Mana from the Cosmos is High. So your blood-creation spell with be a high-change spell. Furthermore it would cost mana to create more blood so it wouldn't be limitless and you'd have to take action to generate the blood, or at least start the generation of the blood. Your wings wouldn't be something you can pop out they'd be something you can create using mana. All these things are the difference between spells and powers that I explained earlier.