Eren had conquered the Western Continent. He had stopped the rebellion of the Holy Priestess with brute force. In the process, he even managed to kill the Main Character of the Western Continent.
With that, he had killed three Main Characters in this world, leaving only the one in the Southern Continent.
He had dealt with all immediate threats, and now he could finally return to the only place in this world that even remotely felt like home.
He could return to the Demon Sect, where many people were waiting for him, not knowing if he was ever going to return.
He had left a clone to take care of the Holy Emperor's place, but his own place was left vacant. For this world, he had just disappeared into nothingness.
Even if many had started thinking of him as dead, he wouldn't have questioned it; after all, he left no proper message behind.
Subconsciously, he was even looking forward to seeing their reactions when he returned to the Sect.