MTL - My Wife is a Beautiful CEO - ~ 1453 [Brother and sister and water fire]

Zheng Tan somehow returns to the year 2003, turning into a black cat. Picked up from a rubbish heap by the Jiao family, he is given the name “Charcoal”, and so begins the life inside Professor Jiao’s family. Zheng Tan remembers that he was once a person, but currently his body is that of a cat. He has no way of speaking the human language, but can understand it, and even retains the thinking and IQ of a young 20 year old youth. Read along as he adapts to this new world, and somehow tumbles from a group brawl to catching a thief.

- Description from Novelupdates

Lu Zhiguang is not a cannon fodder himself, but his mission is to save the miserable cannon fodder.

During a party one evening in the royal palace, Rachel, the eldest daughter of Duke Ferguson, was reproached by Prince Elliot for sins she didn’t remember committing and their engagement was abandoned. Rachel informed everyone she had not committed the acts they were accusing her of, but she was dragged away out of the party venue and thrown into the palace dungeon.

I returned to Earth as the invincible Knight King. But the Gods came with me.