This is another series by Rick Riordan. This one is a modern version of Norse mythology, with Magnus Chase being the demi-god son of Frey, the god of summer, and his Valkyrie and friend Sam is the daughter of Loki, the well-known god of mischief. This series takes place when Loki breaks free from his eternal punishment and starts Ragnarok. Magnus Chase dies and goes to Valhalla(Hall of slain heroes), where he becomes a soldier sworn to prevent Ragnarok and protect the gods. I liked these books but weren’t as good as the Percy Jackson series or Heroes of Olympus.