Many anime involves characters making promises. These promises range from marriage vows between childhood friends to getting stronger and achieving various dreams. These anime often also make true on these promises, much to the joy of fans, no matter how difficult it may be for those promises to be fulfilled.
However, there are some promises in anime that fall through, often with devastating consequences or due to unfortunate circumstances. These broken promises could be deliberate like Damian did to abandon his Charmander in Pokémon, or because of other reasons such as sabotage in Yakitate!! Japan. No matter what these promises were, however, they never failed to break hearts.
10 Kawachi And Azuma Never Got To Fight Each Other In The Newcomers Tournament Finals (Yakitate!! Japan)
In Yakitate!! Japan's Newcomers Tournament arc, Kawachi and Azuma promised to each other that both of them would make it to the finals and battle each other. Unfortunately for Kawachi, Yukino Azusagawa sabotaged his semifinals match against Shigeru Kanmuri by tampering with his flour using endoprotease Kanmuri previously developed (though Kanmuri didn't know Yukino would use it for such purposes). Kawachi ended up losing his semifinals match as consequence. Azuma, however, won his match and ended up in the finals against Kanmuri instead, only to win the entire tournament.
9 Kazune Kujyou Decided To Transform Despite Promising Not To And Almost Died (Kamichama Karin)
After Kazune Kujyou's transformations into his god form started destroying his own physical health in Kamichama Karin, Kazune eventually promised to not transform anymore. Unfortunately for fans and his loved ones, after Karin is kidnapped by Kirio Karasuma and Kirihiko Karasuma took over Kirio's body, Kazune ended up transforming one more time. This transformation, and his use of it, almost killed him in the process. If it wasn't for Karin intervening to help him against Kirihiko, Kazune would likely have died.
8 Damian Abandoned Charamander After Promising To Come Back For It (Pokémon)
In one of Pokémon's early episodes, trainer Damian abandoned his Charmander on a rock after promising to come back for it. After Ash and his friends discovered Charmander still waiting for Damian after all this time, they confronted Damian and tried to force him to take back Charmander. This was especially important since it was going to rain soon outside and it could prove fatal to Charmander.
Despite this danger, Damian refused to take Charmander back, and Ash was forced to rescue Charmander himself. Had Ash and his friends not done so, Charmander likely would have died from the cold rain.
7 Kaori Died Before She Was Able To Keep Her Promise To Perform With Kousei Again (Your Lie In April)
During the events of Your Lie In April, Kaori promised to perform with Kousei again at a later time, but her death during surgery (or due to the surgery failing) prevented her from ever doing so, breaking fans' hearts. This was sad considering the close bond Kaori and Kousei had throughout the series. This also meant that these two would never be able to create beautiful music like they used to.
6 Kaiba Failed To Save Mokuba's Soul During Duelist Kingdom (Yu-Gi-Oh!)
During Yu-Gi-Oh!'s Duelist Kingdom arc, Seto Kaiba set out to save his brother Mokuba after Maximillion Pegasus kidnapped him. By the time Seto finally made it to the castle a second time after the first attempt resulted in Pegasus taking Mokuba's soul, Seto had no choice but to duel Pegasus to get a chance to rescue his brother. Unfortunately for Seto, thanks to Pegasus' Millennium Eye, he lost the match. Not only did he lose his chance to save Mokuba, but he also lost his own soul. Thankfully for both brothers, Yugi does end up rescuing them after he defeats Pegasus in a later duel.
5 The Rumbar Pirates Never Got To Return For A Baby Whale After A Round-Trip Voyage (One Piece)
In One Piece, the Rumbar Pirates left a baby whale called Laboon at the beginning of the Grand line, promising to come back for it after they finished a round-trip voyage. Unfortunately for this band of pirates, they were all wiped out; some died of illness, others left the ship to save their own lives, and the remaining ones were destroyed in battle.
Brook, the only pirate remaining in the end, was only alive as a living skeleton thanks to consuming a Devil Fruit. This revelation broke fans' hearts, realizing that the crew that Laboon cared for so deeply was now long gone.
4 Naru And Nephrite Never Got To Eat A Chocolate Parfait Together (Sailor Moon)
In Sailor Moon's Dark Kingdom arc, Naru (known as Molly in the dub) ended up falling for Nephrite. However, Sailor Moon and the others knew Nephrite from the Dark Kingdom was bad news and tried getting Naru to give up on pursuing him. Naru refused to stop pursuing him because she already fell in love with him by that point. Later on in the arc, Naru and Nephrite managed to talk to each other on a non-manipulative basis after Nephrite saved her life from other youma, with Naru wanting to have a chocolate parfait with him someday. Unfortunately for the couple, Nephrite died defending Naru, much to Naru's grief.
3 Goblin Slayer's Sister Did Not Make It Out Okay, Despite Her Saying So (Goblin Slayer)
During the events of Goblin Slayer, it's revealed that the titular character's sister hid him as a child under the floorboards, telling him to stay quiet until the goblin invasion was over to keep him safe. With a smile, she promised him that things would be okay. Unfortunately for the Goblin Slayer, the goblins ended up assaulting and killing her while the young Goblin Slayer watched in horror.
Considering how dangerous the goblins were already presented as from the beginning of the series, it's unsurprising but still tear-jerking to see that such a promise would not be kept in the end.
2 Kohana Overused Her Powers To The Point Of Near Death (Magic-Kyun! Renaissance)
In Magic-Kyun! Renaissance, it's discovered in the finale that Kohana's sparkles when flower arranging have become snowflakes. Students with snowflake-shaped sparkles have extraordinary talent and sensitivity to the Light of Arte, leading to them intensively devoting themselves to their art and putting their own lives at risk.
Despite being instructed to avoid using her magic any further for her safety, Kohana deliberately broke this promise, claiming that she was not special enough to do so. However, it's this lack of belief in herself as well as her breaking the promise that led to her being in a comatose state. Without assistance from her friends and classmates, she would never wake up.
1 The Children Were Not Being Sent To Live With A Family By Age Twelve (The Promised Neverland)
In The Promised Neverland, it's stated that all the children in the orphanage will be picked up for adoption by their twelfth birthday. Until then, they cannot leave the orphanage grounds. At first, it didn't seem too bad, considering that the children were treated with care (other than the regular rigorous exams and tests they go through). However, the protagonists realized that this promise wasn't being kept at all. Instead, they were actually being raised to be human meat for demons to feast on. This heartbreaking reveal destroyed the protagonists' faith in their caretakers, and so they decided to run away to avoid their untimely fates.