I'm not entirely sure specifically what a 'beerus raps beerus fanfic' is about without more context. It could potentially be a fan - created story where the character Beerus is rapping. Maybe it involves Beerus expressing his thoughts, his powers, or his experiences in the form of rap within the context of a fan - made fictional narrative.
One idea could be a crossover with the Dragon Ball Super universe and the DC Comics universe. Zamasu could team up with Darkseid, believing they share a similar view of bringing 'order' to their respective realms. Another idea is a crossover with the Naruto universe, where Zamasu tries to impose his will on the ninja world, facing off against powerful shinobi like Naruto and Sasuke. Or perhaps a crossover with the Star Wars universe, with Zamasu as a Sith - like figure, trying to gain control over the Force.
You could try looking on fan - fiction websites like Archive of Our Own or FanFiction.net. They usually have a wide variety of fan - created works, and there's a good chance you might find a 'beerus raps beerus fanfic' there.
One interesting Zamasu fanfic could be about his origin story in more detail. It might explore his early days in the Kaioshin realm, his training, and how his ideology started to form.
Zamasu meets his end in the manga because he underestimates the strength and strategy of Goku and Vegeta. They exploit his weaknesses and deliver the final blow that finishes him off.
Beerus would likely be more powerful. He is a god of destruction in his own universe with incredible cosmic powers. Naruto is extremely powerful in his world, but his power is mostly based on chakra and ninjutsu, which is on a much smaller scale compared to Beerus' ability to destroy planets with a flick of his finger.
There were novels similar to Douluo Continent Erasing Tang San:
1."Dragon Ball: I, the Wukong cub, have a combat power of more than 100 million." Author: Rare steak, thank you.
2."From the Peerless Tang Sect to Kill the Douluo." Author: Lonely Whisper of the Illusionary Moon
The following is a detailed introduction of these novels:
1:"Dragon Ball: My Baby Goku's Combat Power Has Surpassed 100 Million": Sun Wukong: "With my previous life's experience, it's not too much to transform into a Super Saiyan before going down the mountain, right?"
"That bastard Kakarot, why is he always stronger than me?"
Virus,[I will become stronger when I meet someone stronger. My strength is unknown!]
"So Wukong is so handsome when he grows up!"
"Thank you, Buma!"
"Mr. Wukong, here's your document."
Just as Sun Wukong was immersed in enjoying his family life.
His future daughter appeared in a time machine.
"Daddy, I'm your daughter from the future.
Mommy misses you very much.
Someone stole your body and started a massacre in the future world…"
Sun Wukong: "So, I wasn't reborn. It was my soul that traveled through time."
It turned out that he, who had been reborn as Sun Wukong in his previous life, had married Buma and killed Vegeta, who had invaded Earth.
Buma also gave birth to a cute daughter for him.
However, when he fought against Sarroux,
A viral heart disease outbreak, no one to help hold the fort.
There was no time to receive treatment, so he was sacrificed.
In the end, when he woke up again, he returned to this world and became the Saiyan cub Sun Wukong again.
2."From the Peerless Tang Sect to Kill Through the Douluo"(Daily Business + Xiao Bai's Cool Writing)
The three Martial Souls were the Reincarnation Heavenly Eyes, the Battle Sacred Body, and the Heavens Sword Box.
He was the invincible Godslayer Pope on the Douluo Continent!
He was the peerless First Emperor who had completed the unification of the Tang Sect!
He was the Holy Dragon Knight who was rumored to be the savior of the Dragon King!
You can read these novels on Qidian Chinese Network.
Well, Naruto could be in awe of Beerus' power. Maybe he tries to learn some of Beerus' combat techniques. Since Naruto is known for his determination, he might pester Beerus to train him.
With King Kai, Beerus as a girl could have a different kind of relationship. She might be more patient with him. King Kai might be a bit more nervous around her at first, but then they could develop a more comical and friendly rapport, with Beerus teasing him in a more light - hearted way.