Books in the Marvel novels series

"When Earth is plagued by an epidemic of fear, ancient prophecy says only Thor can stop the monstrous threat of the Serpent, but without help from Loki, Thor is certain to fail. Aided by a handmaiden from Hel and a demon puppy, Loki must risk everything to find redemption or doom himself for eternity. Either way, a Nightmare lies in wait hoping to rule the world, and Loki will have to risk everything on his craziest scheme of all! Meanwhile, new gods threaten to disrupt the status quo, throwing everything out of balance. Loki must act as a responsible ambassador, but will the Nine Realms end in Surtur s fire? Young Loki must cross the realms to reclaim his own story, outwit ancient enemies, struggle to do the right thing, and avoid falling in love"--