Fullmetal Alchemist fans are doing themselves a disservice by not reading its creator's latest manga
You're making a mistake by not hopping on the Daemons of the Shadow Realm train now.
If you kidnapped me, drove me to an underground broker far away from civilization, put a gun to my head and forced me into choosing the greatest manga/ anime of all time, first of all, please don't do this, and secondly, I probably wouldn't have much of a hard time saying Fullmetal Alchemist. Yeah, yeah, I know what you're going to say, "but what about *insert manga name*" and maybe you're right, but let's be honest; there are very few series that can hold a candle to the highs and lows of FMA.
It's got it all! Misguided but talented brother protagonists on a quest to get their bodies back, an incredibly fantasy world with one of the most original magic systems around, a centuries long mystery, and a surprisingly tight critique of the US' invasion of Afghanistan. I just can't think of a manga that holds up better honestly, but since it finished in 2010, its creator Hiromu Arakawa has gone under the radar a bit for most.
Arakawa hasn't been sitting idly in that time, she's completed several works since then, one of the best being the slice-of-life, coming of age farming manga Silver Spoon, but outside of FMA, you don't hear her name uttered that much outside of superfans. That's a mistake for several reasons, especially because she has a relatively new manga that she's actually been working on for a few years now, one that FMA fans really shouldn't miss out on: Daemons of the Shadow Realm.
For one, if having siblings as protagonists is one of your pre-requisites for reading a manga (weird choice, but you do you), then you'll be happy to know that Daemons has exactly that! It stars twins Yuru and Asa, who were separated unbeknownst to the former. From the outset, it looks like Yuru lives in a mountain village in Japan at least a few hundred years ago, but quickly it becomes apparent that there's more to the world than just that mountain.
Later, Yuru gains the ability to command two spirits, the titular Daemons, and in contrast his sister Asa has special, slightly unwieldy powers. Of course, there are some world ending stakes too, potentially because of these fateful twins, and there are all sorts of groups that seek to either kill or protect them. Daemons is still ongoing, so the story hasn't been resolved yet, but right from early on one thing is clear - from the first chapter, you'll be able to feel that there's a big adventure ahead of you.
I think that sense of adventure is the most appealing thing about FMA. Its world is clearly a big one, and you get to see all sides of it; you really feel like you're a part of the journey with the Elric brothers, even when the pair of them are separated. Arakawa had such a clear vision with FMA that was so stunningly well executed, having the chance to experience something like that again, only as it releases, feels like an experience that would be a massive shame to miss out on.
What I'm saying is, if you sometimes think to yourself "I wish I could experience Fullmetal Alchemist for the first time again" you don't need to anymore, because there's something new and just as exciting to jump into. Conveniently, it is also available officially in English through Square Enix's manga app MangaUp! A story like FMA only comes around once in a while, so you should catch up with Daemons while you still can simply for the fact we're lucky to have it.