Why does bodily damage matter if the whole thing is powered by a mana core? Usually with these things, you'd kill the creature by smashing the mana core. Decapitation makes sense when there's not an obvious battery. And with vampires it's actually usually staking them through the heart.
Is the mana core kept in the neck? Because if it is, that's a really bad design choice. The skull and ribcage are comparatively much safer, since they wrap their organs in a layer of bone. That's why vital organs are kept there.

Are vampires in this? Do vampires also run on a mana core since they'd be a sapient undead? Who would intentionally design a creature like that? Why does their mana core run on blood and others don't?
Does vampirism still spread by biting, or would the vampire have to create and implant an entirely new mana core? And if it's the former, how does a bite create a new mana core?