I don't think this is how anyone was expecting Ronan to come back .
Suddenly this sounds like it's turning into a Thor cartoon .There's the Midgard Serpent, the giant monster that the Avengers fought in the first season of "Avengers Assemble". But there's also Cul Borson, nicknamed "the Serpent", brother of Odin and God of Fear, who recruited 8 powerful warriors as his "childrens" using magic/twisted hammers. I think he's talking about Cul Borson's Serpent.
EDIT 5/12: Speaking of Thor cartoons, I just watched a promo of the Darkhawk arc, and it looks like MCU Valkyrie will be showing up .