Three Realms and Nine Heavens

The protagonist, Lin Fei, is an ordinary student with both parents. His family is not rich, but it is very warm and happy. However, fate chose him, and he accidentally jumped into the world of Greek mythology through time and space. In order to return home, he went through many hardships. But when he returned to his original world, he found that everything had changed. Facing the invasion of alien races, Lin Fei had to use the sword in his hand to defend his own world.