RuneSky: Getting NTR'd in Another World With My Mom and Big Sisters

[NTR STORY: DO NOT READ IF YOU DON'T LIKE THAT SHIT. ALSO WHOEVER HAS A BETTER IDEA FOR A TITLE LET ME KNOW, THE CURRENT ONE SUCKS LOL] One month ago, Shotaro Koyanagi didn't expect to get magically teleported into the world of his favorite game, RuneSky Online! To him, it all happened so quickly. He was simply playing as usual, got blinded by a bright light from his monitor, and found himself in the fantastical town of Grimwalt, the starting town...alongside his mother and both his elder sisters? His family (except his father, who wasn't home at that time) somehow also followed him into the game. After a little bit of confusion, all four family members were met with a status screen, and each saw that they were blessed with a special ability. There was also a notice on the screen, saying that they must "defeat the demon king and his subordinates" to make it back to Japan. A classic scenario. Shotaro was excited at first. He decided it was best for them to do some adventuring as they find a way out. It's fun, and keeps their income stable. With their sheer strength, Shotaro and his overpowered family became the second strongest party in the Grimwalt Guild! To his happiness, his family also seemed to be exploring new areas, killing monsters, and helping out the common folk. Despite that, he can't help but feel like the dynamic between them was…starting to grow different. Especially as they meet some of the various NPC's in RuneSky.