Start in DxD as Motohama: Leveling Up in Another World - Chapter 4: "Leveling up benefits. Garden and Hell’s Slime"

Ruins stretched across the landscape in the apocalypse after the nuclear war.

The Great Yan Empire exists in a world where respect can only be earned through strength. Within this Great Yan Empire, the four great clans have always stood above the rest. Among them, a particular incident in the Lin Clan resulted in the banishment of a certain individual who went on to start his own family, in hopes of one day being recognized again by the Lin Clan, and rejoining them…

Depth-Dwellers are long extinct.All except for a single one..Waking up after being dragged by the pressuring tides, Cetas finds himself in the middle of an unfamiliar ship, greeted by a distinct group of pirates.Without any knowledge about humanity at all, he traverses the seas with the unknown band of pirates and learns about their culture and speech. In a world where 'Zeal' serves an essence for humanity's power, Cetas must learn to ascend the ranks to protect those that he cherishes.For when the mysteries beyond the fog arises, the Dreadspawns begin to wreak havoc, and the Leviathans rise up into the world..'Would Cetas become a 'human' worthy of saving those that he loves?'

Ye Chu is a miserable supporting character from a novel (she transmigrated).

She’s the most famous socialite in Shanghai, but her existence was to emphasize the magnificence of the white lotus female lead.

In the previous life, Ye Chu died in an accident. After rebirth (still in the novel), she didn’t only want to get revenge, but also change her fate, allowing every side character to have the opportunity to shine. Ye Chu and Lu Huai are a fake couple in their previous lives but reunited in this life.

They probed each other at every turn and slowly got closer to each other. They two fell for each other and confronted their enemies together.

- Description from Novelupdates