I'm fairly certain it is a story series that starts with Loki appearing unannounced at the tower and leaving one (or maybe it was two?) of his children to looked after and protected by Tony. Tony didn't really get a say in the situation as Loki had urgent matters elsewhere. Over the course of the first(early) story eventually all of his children (Jormungand, Fenris and Hela) join Tony at his tower. At one point later on Tony gets sick with the flu and the children were all very concerned about him. I think Jormungand shifted to his snake form to better monitor Tony and provide warmth if needed? I think. Does this ring any bells? Any help will be greatly appreciated. Thanks in advance.