Is Blood Magic considered egocentric?
I'm not entirely sure what you're referring to. I'd appreciate, for questions like these, if you would include an example of a character or series. "Blood magic" is a generically spooky term that gets used in a lot of fantasy and horror content, and it doesn't always mean the same thing. The Marvel wiki gives a few different examples, and I'm pretty sure there are even more out there.
Marvel Tarot defines ego-centric magic as that which is "derived from tapping into one's own spiritual energies." If you are using your own blood to cast or fuel a spell, then, yes, that fits the definition, in the sense that you're drawing power from yourself, your body, your lifeblood. There are a lot of characters, including most witches, whose magical power is hereditary, and that's sometimes described as a "bloodline." In this instance, the power is an inherent part of the person, so again, that fits the definition of ego-centrism.
Blood and other body parts can be use in spellcasting and rituals for a variety of purposes. We've seen blood used to create a connection to, or invoke the properties of, the person it belongs to-- I'm thinking of how Coven Akkaba would use mutant blood in Excalibur. In real life, this is usually described as sympathetic magic-- "sympathetic," in this case, referring to the symbolic or literal connection between two objects. Broadly speaking, you might describe this as eco-centric-- utilizing the power of your surroundings.
With blood specifically, however, it may better suit the definition of necromantic magic, which as I mentioned here, derives power from death and sacrifice, and ostensibly originates from the Darkhold. One need only look to vampire lore in the Marvel world to see how there may be overlap between the Darkhold, blood magic, and necromancy. In real life, "necromancy" means something very specific, but in Marvel, it seems to describe any kind of dark magic that is fueled by draining or consuming the energy of other life forms, at least in any way that is harmful or unsustainable. We know that this is what Lore does, and I would say that the Emerald Warlock's methods in Scarlet Witch (2016) are very similar.
Runaways (2003) #5
The primary example of blood magic on the Marvel wiki is actually Nico Minoru's Staff of One. In the first three volumes of Runaways, Nico must shed blood in order to summon the Staff and invoke its power-- once summoned, the Staff can cast virtually spell without further cost. If you assume that it is Nico's own lifeblood fueling the spell, then that's textbook ego-centrism. Nico's magical abilities are hereditary, and the Staff itself is literally bound to her bloodline, so that fits the definition of an innate power. However, the idea of sacrificing one's blood hews closer to necromancy, and in the 2017 series we learn that the Staff is actually an imprisoned magical entity whose power is being abused against its will. In exchange, in consumes blood, and later, portions of Nico's soul. I think that this is actually a really good example of necromantic magic, as it's defined in Marvel Tarot.
Two things to note-- first, the idea of magic blood, or "witches' blood" can sometimes be used in a way that's really racist, and it's something that I'm especially wary of with Romani characters. Personally, I think it's a matter of tone and intention, and you can put a really positive spin on the idea of magic bloodlines, even in a family like Wanda's. But the idea that her blood itself is literally magic is probably something we should avoid.
