In other cases, the ending might be bittersweet. The main character may sacrifice themselves to stop the monster menace. Or, the world might be changed forever because of the monsters, but the survivors learn to adapt and build a new kind of society. Consider an anime where a horde of powerful monsters has invaded and destroyed much of the world. In the end, the remaining humans use the ruins and the power left by the monsters to create a new and different civilization.
Some monster anime stories end with a revelation about the origin of the monsters. This could lead to a new understanding between the humans and the monsters, resulting in coexistence. For instance, if the monsters were created due to some scientific experiment gone wrong, and in the end, the humans find a way to reverse the process or live in harmony with the monsters.
However, there are also sad endings. In '5 Centimeters per Second', the main character Takaki Tono has a series of unfulfilled loves. The story ends with a sense of melancholy and longing as he and his childhood love, Akari Shinohara, have drifted apart over time.
Often, they end happily with the main couple getting together. For example, in 'Fruits Basket', Tohru Honda and Kyo Sohma end up in a loving relationship after all the trials and tribulations they've been through.
Some end happily with the monster boyfriend and the human (or other character) staying together, like they overcome all the odds against their relationship.
Often, one person in the love triangle ends up with the main character they are meant to be with. For example, in 'Inuyasha', Inuyasha finally chooses Kagome over Kikyo. Another way is that the character in the middle realizes they don't have romantic feelings for either of the other two in the triangle and decides to be alone or just be friends, like in some less - common storylines.
Often, they end happily with the couple getting together. For example, in 'Fruits Basket', Tohru ends up with Kyo, and they have a future together filled with love and understanding.
They often end happily. For example, the couple gets together and lives happily ever after, like in 'Fruits Basket' where the main characters find love and also resolve their family issues.
Often, they end with the main couple getting together. For example, in 'Kaichou wa Maid - sama!', Misaki finally realizes her true feelings for Usui and they end up as a couple.
Some love stories end in a more bittersweet way. The couple may part ways, but they have grown and learned from the relationship. They might still have love for each other, but they realize that they are better off apart for various reasons, such as different life goals or personal growth directions.
They often end happily, with the couple getting together. For example, in many classic romances, the two lovers overcome all the difficulties and start a new life together.
Well, dystopian stories often end with some sort of hope or change for the better. Maybe a group of characters manages to overthrow the oppressive system or find a way to restore balance.