Oukoku e Tsuzuku Michi - Chapter 578

[You have entered the dungeon at Gwachun Station’s 1st Exit.] When former high school student Kang Woojin finds himself returned back to Earth after being forcibly summoned to a foreign planet for 20 years, he soon finds that Earth is not the same, normal place as he once remembered it to be.

Wen Er girl is unparalleled in beauty, but when people mention it, she has to sigh because she was born dumb. Unexpectedly, one day, the second girl Wen, who fell from the wall and hit Prince Jing’s body, suddenly spoke.

- Description from novelbuddy

Ukei Kaito fought a desperate struggle in order to fulfill his role as a summoned hero. He defeated the Demon Lord and saved the very world, only to meet an end filled but with betrayal. The companions that he’d trusted throughout his journey betrayed him and killed him by sticking a blade through his chest.

My old man pointed to the flower-like woman and said, "Call her mother from now on." He then pointed to a flower-bud-like girl and said, "This is your little sister."