Eroth transmigrated into a world of swords and magic. To make up for the mistakes he had made in his previous life, he chose a girl who seemed to desperately need someone to care for her as his older sister. He swore to do everything in his power to raise and protect her, and fulfill her every need and wish.
But as it turned out...
"Eroth... Hehehe... My dear Eroth, do you know how many times we've had our first night together?"
Eroth: "?"
"It's all right, just relax. Leave everything to Big Sis."
Why is my sister a Demon Lord who keeps being reborn?!
"Eroth..."
"Eroth."
"Eroth!"
And you lot! Don't come any closer! Is anyone there? A bunch of people are about to commit a crime against an innocent young man!!
