Final Fantasy Lost Stranger Series by Hazuki Minase

Square Enix employee Shogo Sasaki has a big dream-to produce his very own Final Fantasy game with his sister, Yuko. But after the siblings are involved in a truck accident, they awaken to realize they've left their world behind...and fallen into the world of Final Fantasy! After coming to grips with the situation, they meet some new friends, join a party, and accept their fate as adventurers... moreSquare Enix employee Shogo Sasaki has a big dream-to produce his very own Final Fantasy game with his sister, Yuko. But after the siblings are involved in a truck accident, they awaken to realize they've left their world behind...and fallen into the world of Final Fantasy! After coming to grips with the situation, they meet some new friends, join a party, and accept their fate as adventurers. But when danger approaches, Shogo will discover that his encyclopedic knowledge of the games can only take him so far... less

Shogo and his party continue their trek up the mountain. At the summit, the dragon that killed his sister awaits. The group's perseverance has earned them a spot on the raid team, but the respect of Randolph, the raid's leader, is another matter entirely. All is silent... and then suddenly, the dragon is upon them. Throwing caution to the wind, the adventurers pelt the creature with arrows, spells, and strikes, but their efforts are in vain. In an instant, the team is decimated... moreShogo and his party continue their trek up the mountain. At the summit, the dragon that killed his sister awaits. The group's perseverance has earned them a spot on the raid team, but the respect of Randolph, the raid's leader, is another matter entirely. All is silent... and then suddenly, the dragon is upon them. Throwing caution to the wind, the adventurers pelt the creature with arrows, spells, and strikes, but their efforts are in vain. In an instant, the team is decimated. Randolph orders the few who escape the beast's wrath to retreat, but one man remains, standing tall amid the falling snow... less

After being captured by the Magus Sisters, things are looking bleak for Shogo and his party of adventurers. Cindy's very interested in his 'Libra' ability, and she'll stop at nothing to have it for herself...

With the broken remains of Calcabrina strewn about the castle grounds, Shogo and his party can finally breathe a sigh of relief. Yet Princess Sara's adulthood ceremony looms on the horizon, and an attack by the Magus Sisters seems inevitable. Will Sara and her new friends be able to protect the relic that sleeps within the cathedral?

Shogo and friends continue their search for "Raise," the spell that will bring his little sister back to life. Their search leads them to Mysidia's Royal Library, where they find tons of musty, old books, including one that seems to be speaking to them...!