okokok sooo i recently re watched rottmnt (again) and re-read my full metal alchemist manga and i feel like they have ALOT of things in common, and i feel like sharing em bc these are two of my favorite shows.
FIRST OF ALL (the most obvious connection) they both have HUGE elements of alchemy. in rottmnt baron draxxum literally calls himself a warrior alchemist and created the tmnt USING ALCHEMY, and creates the turtles basically through alchemy. in full metal alchemist yk THE MAIN PLOT IS HOW THIS ALCHEMIST DUDE AND HIS BROTHER ARE TRYING TO GET THEIR BODIES BACK AND HAS SEVERAL STORY PLOT POINTS THAT HEAVILY CENTER AROUND ALCHEMY. one of these huge plot points is how this guy transmuted a dog and this girl to make a chimera or in rottmnt terms A MUTANT.
another rlly big thing they have in common is the idea of the power of brothership and family and stuff. in rottmnt it heavily centers around their family dynamic and how the brothers look out and would do anything to protect eachother. in the full metal alchemist: brotherhood, THE TWO MAIN CHARACTERS ARE ALSO BROTHERS AND PROTECT EACHOTHER THROUGH THE ENTIRE SERIS.
Another thing i found interesting between the two seris is abt rise's shredder. if we're taking his backstory at a basic level, it's basically abt this guy who got this suit of armour, but then his soul got curropted and had to be locked in the prisoon dimension. once he was unlocked he was basically a corrupted soul bonded to the dark armour. WANNA KNOW WHATS THAT SIMILAR TOO?? one of the main characters, alphonze, tried to tranmute his mom with his brother, but got his body taken away, so then his brother had to bond his soul to a suit of armor. SO THEIR BOTH SOULS BONDED TO A SUIT OF ARMOR. also within the full metal alchemist: brotherhood seris theres also two more of these types of armor dudes. one of these dudes, barry the chopper, his design looks very similar to sheedders design so i thought that was cool.
and then i might be stretching with this one BUT in the rottmnt movie we see that future leo is wearing raphs arm or something and its kinda implied that he lost his own arm, and raph might've gave leo his arm before he died or something during the krangg war invasion thing. also in the krangg war, the krangg is trying to kill and exterminate everyone on earth. this is kinda like in full metal alchemist, during a flashback about the ishfallen war of extermination (which was a war were the government had to kill an innocent group of people called the ishfallens, ik this seris gets like, pretty dark-) the character, scar, loses his arm, and before his brother dies, his brother transmutes his own arm onto Scar. so basically in both it has a dying brother giving up an arm to the other brother during some type of war.
and then this one is kinda an even bigger stretch but, in full metal alchemist all the villains are heavily based on the 7 deadly sins, and even their names are lust, greed, envy, ect. I feel like you could also kinda connect the rottmnt villains to some of the deadly sins. first, we have repo mantis, he would def. be greed because he's always repoing stuff for money. then warren stone, might be pride, because through the whole seris of rottmnt he thinks hes some big bad villain, when literally no one cares abt him (exept hypnopottumus). gluttony would be meat sweats, cause his literally a pig who gains power from what he eats and stuff. lust could be big mama because like, she pulled lou jitsu with little to no effort, and used him for the battle nexus. The rest of the sins im not too sure, i havent rlly throught abt that connection much- but you get the idea i hope.
anyway that's basically it, i could go more into depth but i think this is a big enough infodump to read lol. i wouldn't be surprised if rottmnt took some inspo from full metal alchemist. but thats just a theory A GAME- no wait A FILM THEORY have a good day :>