I was reincarnated in another world to protect what I was unable to do

Synopsis:

This is a story about a brother that was reincarnated in another world to protect his little sister in the shadows.
Leon was a simple high school student that loves his little sister so much but his little sister treats him badly everything changes when his little sister was summoned to another world with her friends and they became the heroes of that world.
While that happened Leon waste his remaining life span on earth searching for his little sister and when he died, he was given another chance by a goddess to live his life peacefully in another world where his long search for his sister ends and he was able to reunite but he decided to stay in the shadow as a mob character while protecting her