Sorry this is late! Stuff happened. Lots of really annoying stuff.
Out of everything I’ve watched, by far Fullmetal Alchemist: Brotherhood does the best job of making the comic relief and the sheer darkness of what’s happening work together. Most dark works (which, FMA:B isn’t dark overall, but has a lot of darkness in it) use comic relief to punctuate the darkness, but the jokes feel external–at best they’re characters whistling in the dark to put up a brave front, at worst they’re just completely artificial-feeling. But in FMA:B the jokes aren’t ever just jokes. Armstrong is hilariously weird and sparkly, but he has a really tragic backstory that comes up occasionally as a reason he’s determined to see things through. Hughes is hilariously weird and wiggly, and we all know what happens to him. Ed being short starts as a running gag and ends up being a plot point!
I am actually really jealous of Arukawa’s writing ability. I wish I understood better how she does it, because I *suck* at writing humor, let alone seemlessly integrating that humor into a serious narrative.