Definitely has to be Hughes' passing from FMA in both FMA and FMA Brotherhood was awfully sad it was awful to see such a great man pass in the fashion he did.
Grave of the Fireflies:
*Main character dies immediately. Flashback to his last days on earth.
*Bomb dropped, house destroyed.
*Kids find mother in a hospital wrapped head to toe in bandages. She dies.
*Relatives treat kids like crap. Woman nags little boy to join military.
*Children become homeless, live in a cave.
*Sister (a toddler) dies of malnutrition.
*Boy learns that his father's plane was shot down.
Barefoot Gen:
*Bomb drops on town. Children, babies, & a dog are burnt up, liquefied, & showered with shards of glass.
*Main character loses his home.
*Caved-in roof crushes dads skull.
*Mother watches helplessly as her children burn to death. Stress causes premature birth of child.
*Boy starts to show the same symptoms as a man he watched die of radiation poisoning. Safe bet he has cancer now.
*Boy & adopted brother get jobs to buy milk for the baby because the mother has no food to make milk. The baby dies of starvation.
There is absolutely no scene (other than the Code Geass R2 ending) that is more tear-jerking than this ending scene to Angel Beats.
(Though I think some of the feeling was lost with the translation and terrible dub.)
In an anime called Tokyo magnitude 8.0 its one of the saddest moments of anime ive ever seen, i cried through 2 whole episodes 40 min and then i cried more later 😢