 If you liked
Ryuusei no Rockman
|
 ...then you might like
Majin Bone
|
Both main characters are subjected to an other worldly being encounter that turns them into a hero. They as well try to keep it a secret from their close friends and/or family.
Both main characters have a parent distanced from them in outer space.
Both of the main characters have a strong will and determination to fight to protect.
Both series have beings from another world come and antagonize the earth.