Manhwa where the main character is sent to another world after his family is killed

Question

Manhwa where the main character's family is killed. He gets sent to another world where he trains nonstop and beats the demon king, but his true goal is to get back to Earth and kill the one who killed his family. In the manhwa, the Earth is divided and shared by the heroes who returned from worlds and took over.

Answer 1

This is likely The Warrior Returns. It is available on Webtoons.

After saving one world, warrior Minsu Kim returns to Earth only to find that he’s lost everything... so he decides to destroy the world he used to call home. In his rampage, he kills teenager Jeongsu Park and his family. But instead of dying normally, Jeongsu is transported to another world, where he finds that he's now a warrior himself. After killing the demon king of this alternate world and honing his skills as a warrior, Jeongsu returns to earth, hell-bent on revenge against Minsu.

Chapter 1 is backstory for the villain; he becomes a hero in another world, saves it, goes back to Earth, and discovers that his life is a mess. He decides that everyone else should be as miserable as him and starts killing everyone using her otherworldly superpowers.

Chapter 2 switches to another character, a regular teenager fleeing from the previous chapter's villain's rampage. This includes a scene on a highway where everyone is stuck in traffic as the warrior shows up and kills them all, including the protagonist's sister. By chance he survives this, tries to attack the warrior, but is promptly killed and reincarnates in another world as a warrior.

Chapter 3 switches to yet another warrior; I believe this is an indication of the "Earth is divided and shared by the heroes who returned from worlds and took over" from the question.