To many shōnen fans, Fullmetal Alchemist is definitely one of the best shōnen masterpieces of all time. Written by Hiromu Arakawa, the manga started serialization in 2001 under Square Enix’s Monthly Shōnen Gangan until 2010. Since then, there have been two anime adaptations and two movies; along with light novels, video games, and various merchandise.
Set in a world where alchemy is commonly practiced, the main rule is the law of equivalent exchange—one has to give something of equal value in exchange for whatever they’re creating or transmuting. The story follows the Elric brothers, Edward and Alphonse, on their journey to find the philosopher’s stone. The two of them tried to revive their dead mother using alchemy when they were kids—which resulted in a failed attempt and they lost parts of their bodies.
For new or interested fans, the fact that there are two anime adaptations of Fullmetal Alchemist might be confusing. The first adaptation, Fullmetal Alchemist (FMA), was released in 2003 and ran until 2004. It has a total of 51 episodes. Since the manga was still ongoing during this time, it’s the adaptation that’s not the most faithful to its source material.
Fullmetal Alchemist: Brotherhood (FMAB) is the second anime adaptation, released in 2009. It is not a sequel to the earlier adaptation. It’s also longer than FMA, having a total of 64 episodes. You can consider it a reboot since this adaptation is the one that’s more faithful to the manga considering the time frame.
Although it should be noted that there are numerous differences between Fullmetal Alchemist and Fullmetal Alchemist: Brotherhood. One main difference is the antagonist of the story. FMA has a character named Dante as the antagonist, while FMAB has Father. Overall, there are many differences in the other characters too. It can also be argued that FMA is more emotional than FMAB, in which the latter has a lot of comedic moments.
So whichever you want to watch, both adaptations have their own pros and cons, depending on your cup of tea when it comes to watching anime series. Although, a significant number of fans prefer FMAB over FMA as a whole—plot-wise, animation-wise, and character-wise.