Pythons and venomous snakes are two different types of snakes, and there are great differences between them. Pythons were non-poisonous snakes that hunted their prey by coiling, suffocating, and devouring. Pythons were huge and powerful. They could easily suppress and devour other snakes. Even the most venomous king cobra was insignificant in front of pythons. Venomous snakes relied on venom to hunt and defend themselves. Different types of venomous snakes had different venoms and attack methods. Therefore, it was not easy to compare between a python and a poisonous snake. It was impossible to simply say which was more powerful.
The 'poe vs the black cat story' is often filled with elements of horror and psychological turmoil. Poe's use of the black cat as a symbol is very interesting. It could represent the narrator's own dark side or his guilt. The way the narrator's relationship with the cat deteriorates is a key aspect, showing his descent into madness.
One interesting storyline could be Perospero using his powers in unique ways to solve problems in the Big Mom Pirates. For example, his candy-based powers might be used to create elaborate traps for enemies.
His sister, Charlotte Smoothie, could be a great pairing. They both have unique powers and their interactions could lead to interesting story developments, like teaming up for a mission within the Big Mom Pirates.
Man vs. Wild: The Almighty King was an urban novel written by a cat detective. The story was about the protagonist, Chu Lan, who was reborn into a parallel world and participated in a live broadcast called Man vs. Wild for 400 Days. In the game, Chu Lan had obtained the god-level wilderness system and displayed her superb survival skills. He could easily solve problems and enjoy life while other players were hungry, chased by beasts, and troubled by the cold. Master Bei praised Chu Lan's ability to survive far beyond his own, claiming to be Chu Lan's king of the wilderness. The plot of this novel was closely linked and fascinating. It was a highly respected urban novel.
One common theme could be family loyalty. Since Perospero is an older brother, stories might explore how he protects and guides his younger siblings in the context of an original character's story. Another theme could be power dynamics, especially considering Perospero's abilities in the One Piece world.
The Black Cat is often seen as more of a thief with a bit of a wild side in the Marvel realm. She has powers like bad luck probability manipulation which affects her foes. Catwoman, on the other hand, is more about her acrobatic skills and her cat - like grace. In the Black Cat vs Catwoman story, their fighting styles also differ. Black Cat might rely on her powers and her own brand of cunning, while Catwoman uses her agility and knowledge of Gotham's alleys and rooftops to her advantage.
The themes in 'poe vs the black cat story' include the power of the subconscious. The narrator's growing hatred for the cat may be influenced by his subconscious mind. Also, the theme of isolation is present. The narrator seems to be isolated in his own world of madness, and the cat is a part of that isolated existence.
A common theme is the battle between good and bad. Spiderman represents the good, always trying to uphold justice, while Black Cat often toes the line between right and wrong. Another theme is the attraction they might feel for each other despite being on opposite sides, which creates a lot of internal conflict for both characters.
I'm not sure of a specific 'perospero older brother oc fanfic' off the top of my head. You could try searching on fanfiction websites like Archive of Our Own. They have a large collection of One Piece - related fanfics which might include what you're looking for.