Throne of Magical Arcana - Chapter 830 - “Karl”

Yang Feng somehow transmigrated into a different world and received a legacy of an ‘ancient high tech’ family, which does not directly raise his power, but gives him the technology to build things which are way more advanced than the seemingly medieval world.

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

- Description from Novelupdates

Selene Valor, a pureblood vampire, entered a marriage of convenience with her husband Gabriel Valor to protect herself from relatives eyeing what was left of her family's wealth. Six months into their marriage, Gabriel is sent away to war to fight for the kingdom. As time went on, news of his victories spread across the kingdom and he was labelled a hero.Nearly six months later, Selene eagerly awaits the return of her heroic husband. Upon his arrival, Selene is faced with betrayal as he brings home a woman named Cassandra Avery, a human who he introduces as his lover. Selene is heartbroken and tries to save what was left of her marriage but soon there is news of Gabriel wanting to take Cassandra as his second wife.Selene is left with the choice of accepting Gabriel’s wishes and staying protected or seeking a divorce. After a heated argument, Selene turns to someone she never expected to be her saviour. She finds refuge with Lord Xavier Blackthorn, another pureblood who seeks her hand in marriage.Will she forgive her first love or move on to accept Lord Blackthorn’s love?

The person whom the world revolves around.