So I'm a Dragon, So What? - Game System - Chapter 31: Imaginery Tree!

A Count’s Daughter who lost in the running to become the Second Prince’s fianceé, Camilla. The Prince chose a Baron’s daughter as his fianceé, and the world blessed the two’s love as fated. On the other hand, Camilla who was tailored and elevated as the love’s villain in the end, as punishment she was made to marry a terribly fat and ugly man――called『Toad of the Swamp』from his appearance, a lord of a remote region named Alois.

“From death to becoming the master of death, that's my story”[... ]Jake never got a break. Born unlucky, lived cursed, and died alone—struck by lightning on a rainy night. That should’ve been the end.But fate had other plans.In the space between life and death, he meets the goddess of Karma and Fate, who admits his entire life was a mistake—her mistake. To make amends, she offers him a second chance in a brutal new world ruled by magic, martial arts, and monsters.Before he's sent off, Jake draws from five Legendary Cards—and chooses the most powerful of them all: The Legendary Necromancer.Now, Jake awakens in a world where strength decides everything. With his unique talent, he can summon undead endlessly—and harvest power from the souls of his enemies.[You have enough Soul Shards.][Undead Dragon summoned.]But Jake is suddenly thrust into the Hundred Trials that comes once every hundred years in this new world, a deadly proving ground for the elite.To the others, he’s an outsider—unregistered, unknown, and unwelcomed. A threat to be erased.But Jake didn’t crawl out of death to get killed againLet them come.He has death on his side.

When proposing, Gu Ningxi praised Tao Xinhe for her “perserverence and responsibility”, and on his wedding day, he vowed in public to “be one and only pair for life”.

Tao Xinhe believed it, believed it deeply, and devoted herself to being a good, virtuous wife for her faced blind husband.

Knowing that Gu Ningxi sees everyone as a tile face, she does not change her clothes or incense, and finally let him rest assured to embrace her;

She accompanies Gu Ningxi to the banquet and party, and mentions the names and origins of the guests, so that he can get rid of his arrogant name;

She accompanied Gu Ningxi while he misses his mother, endured the cold face of her grandmother, and dealt with the entanglement of her uncle and aunt, so that he would have no worries.

Yet nothing compared to that— Gu Ningxi could see Mo Qiqi’s face. In his eyes, only Mo Qiqi was vivid and pleasant, and the faces of the others were blurred.
He focused his eyes on Mo Qiqi, coaxed her softly, and allowed her to touch him. For this reason, he deceived and neglected his wife, and he couldn’t recognize Tao Xinhe who had changed her clothes.

Tao Xinhe’s heart died, determined to go, she left a letter of divorce. Her father and younger brother treated her like a jewel, she regained her spirits, and when she heard the news of her ex-husband taking Mo Qiqi into the mansion, she only smiled.

- Description from Novelupdates

The strongest Demon Lord dies, and reincarnates as a human. Not only that, he because of various incidents turns into the hero’s best friend.

Follow his journey as he tries to help the hero escape his fate, and on the sideline to conquer the continent while he’s at it.