Different Blood Group

Those who are not from our tribe must have different thoughts! The mystery of the alien race has been engraved in the boy's heart since the day his parents died. The train the boy and his parents were traveling on was attacked by aliens because an unknown "big shot" was on board. He was thrown off the train by his parents seconds before the train was blown up, holding in his hand a letter left for him by his parents. The boy didn't care why he was not injured and opened the letter bathed in blood. The text inside was obscure, and he could only understand a line of marked text. "The era of aliens will eventually end!" Perhaps it is at this moment that the journey between the boy and the alien race begins...