Simpel Down Bad is so fucking good, such a hilarious arc too. Magellan was such an amazing antagonist and looked like he walked out of DBZ kinda.
Hannybal was actually compelling snd tragic in a way and truly earned his promotion to Warden.
Impel Down also gave us Domino, Sadie-chan and that one prisoner who got turned into a hot babe so Nuff said.
Also gave us another truly profound, heartbreaking and powerful, but magnificent, endearing, inspiring etc moment with Bon Clay. That legend sacrificed himself multiple times for the SHs, constantly risking his life and almost dying to Magellan for Luffys sake. he was ride or die and always will be. The ultimate bro. He deserves to be a Strawhat officially over anyone else, if I could only pick 2 more I'd pick him and Vivi (Carue would be included though).
Impel Down was amazing. So underrated. It also gave us THICCBAE/jinbei, CROCODILE GOING WILD snd the start of his big damned anti hero arc, devil fruit awakenings, Buggy and more gangster Galdino. Galdinos reaction to reuniting with Crocodile (B-B-B-B-Bossu) and also that one gag wuth Buggy about all the prisoners being unleashed and thus the "perverts" (Okamas) too.
I love this arc so fucking much despite how much I hate Marineford especially now. but Marineford has some amazing and surprisingly hilarious moments and many memes too ofc. Mihawk's infamous ruler measuring distance meme vs Whitebeard lmao.
Also the impel down staff designs are top tier and Impel downs extremely horrifying design too itself. Different versions/levels of hell from Buddhism and such. I remember thinking each floor was made by am awakened userr of a devil fruit long before the current users had them, like Dazs dice dice fruit for the cutting hell floor. yami yami maybe for floor 6 maybe funnily enough lol or the theory that pika pika awakening can steal/absorb light from the surroundings.
Some gorosei abilities and inspirations match the impel down floors and Nusjuro has Buddhist influences potentially.