Tsundere cat heart demon bottom × amnesiac cat-loving top
As the first heart demon in the cultivation world to marry the person he was born from, Huai Shu felt deeply moved.
Who could have guessed that, during their Daoist marriage ceremony, a sudden bolt of heavenly lightning would strike him into another world?
"The 18th Demon Cleansing Conference of Xiancheng"
Huai Shu and the gathered superpowered folk outside the conference room stared at one another.
Looks like I've wandered into an enemy stronghold in another world. Help, anyone online?
As a heart demon with cultivation, Huai Shu naturally blended into the ranks of the superpowered, becoming a conscientious captain at the Bureau of Anomalous Affairs so he could find his beloved.
Perhaps something went wrong with the heavenly lightning that sent him here. By day, he's an S-rank superpowered who slaughters demons like there's no tomorrow. By night, he turns into a... cat without a shred of cultivation?
Bad news: One night, a cat trafficker abducted him.
Good news: The person who rescued him was the beloved he'd been searching for!
Even worse news: His beloved, his partner, his Daoist spouse had lost his memory!
Shu Huai had lost his memory.
All he remembered was that there was someone very important to him, someone who was his... what kind of demon again?
Luckily, this world had plenty of demons stirring in the shadows. Shu Huai was overjoyed, fighting and beating his way to becoming the demons' leader.
Then one day, he locked eyes with a cat and fell for it at first sight, saving its life.
Bonus scene:
On a dark and windy night, the Bureau of Anomalous Affairs team, fully armed, cautiously knocked on Shu Huai's door.
"Hello, Mr. Shu. We've detected intense demonic activity in your home. Your cat may be a world-ending demon!"
The actual demon leader, Shu Huai: ...
Huai Shu, who diligently slaughters demons by day and turns into a cat to keep his beloved company at night: ...
Your captain is sprawled on the floor, meowing sadly at you, then swats you with a paw.
1. The bottom is the top's heart demon, so it's kind of pseudo-selfcest. They look exactly alike.
2. Both are pure, 1v1.
Theme: A kitten saves the world.