Escape from Marriage 100 Days: Sweet Wife Steals a Treasure - Chapter 7 - Guardians were amazing.

Demons and Beast descended, terrorizing the whole world for the past hundred years. Everyone can awaken a grimoire and summon a beast during their age of ceremony. Lucas, awakening the weakest grimoire, also awakened the weakest beast- a small dog with no combat capabilities. Fortunately, as a transmigrator, Lucas also mysteriously awakened a system that allows him to evolve his summons into their mythical beast counterpart. Follow Lucas and his journey to greatness as he evolved his beasts into never been before seen mythical creatures.

Xue Ling is a nine tailed fox who has been cultivating for thousands of years but lost all his tails in a moment of capriciousness.

After 20 years of dedicating his life to opera ever since he had quit the performing arts high school, he had failed at an interview. Losing his motivations, Jo Yunjae depended on alcohol to live out his days until one day, he had been sent back 20 years in time, to the day before his high school admission.

“Why is the thing you summon always so strange, can’t it be a little more normal?”

Lu Yu looked helplessly at the guy who was waving his tentacles in front of him.

“Who made me look up to see you every day…”

- Description from novelbuddy