The lost twin

Everyone knows the story. Voldemort attacks the Potters. Harry survives. But the history books are wrong. There were twins. When Lily's protection activates, the magic becomes unstable because there are two children. Instead of protecting both the same way, the spell tears open a rift between realms. Harry stays in the Wizarding World. His twin disappears. Everyone believes the second baby died. Even Voldemort never realizes there were two children. The rift doesn't send the baby randomly. It sends her to Ninjago.