The fairies I flirted with in the game became real?! - Chapter 5 - Did I Eat Too Much?

A military enthusiast with dreams of serving, shaped by his father’s influence and a bookshelf full of war theories, finds himself unexpectedly reborn into a fantasy world he’d recently read about.Now an orphan, he faces impending destitution in a land governed by strict caste systems. But with the Reich Empire Academy Entrance Exam as his potential salvation, he’s armed not with magic, but with a vast knowledge of military tactics from his past life. As the date of his expulsion from the orphanage looms, he’s determined to leverage his unique skills to change his fate.

Childhood sweethearts.
The most popular person in school is my childhood sweetheart.

- Description from Novelupdates

Eight hundred years ago, Xie Lian was the Crown Prince of the Xian Le kingdom. He was loved by his citizens and was considered the darling of the world. He ascended to the Heavens at a young age; however, due to unfortunate circumstances, was quickly banished back to the mortal realm. Years later, he ascends again–only to be banished again a few minutes after his ascension.

A Deadly Secret, also translated as Requiem of Ling Sing and Secret of the Linked Cities, is a wuxia novel by Jin Yong (Louis Cha). It was first published in the magazine Southeast Asia Weekly (東南亞周刊) and the Hong Kong newspaper Ming Pao in 1963. Its original Chinese title was Su Xin Jian before Jin Yong changed it to Lian Cheng Jue. The story revolves around the adventures of the protagonist Di Yun, an ordinary young peasant, who is imprisoned after being framed. In his quest for vengeance, he accidentally acquires the Liancheng Swordplay manual (連城劍谱), an ancient artifact not only prized for the skills detailed inside, but also for containing a secret leading to a treasure.