City of Bones
City of Bones by Cassandra Clare has many similarities with The Lost Hero. In The Lost Hero, Jason wakes up not knowing anything about himself because his memory was stolen. In City of Bones, the protagonist, Clary, also had memories hidden. In both books, an important character has been kidnapped, and the characters work together to try to rescue her. The characters in both series have to fight mythical monsters to protect mortals and themselves. In both books, a veil that blocks their world from mortal eyes is present-- the Mist in The Lost Hero and glamours in City of Bones. Additionally, in both books, the main character discovers that they have an older sibling.