In some fanfictions, a heartbreaking scene might be when Hiccup sacrifices himself to save Astrid from a powerful enemy. He might push her out of harm's way just as a deadly attack is about to land on her, and then he takes the full brunt of it. The moment when Astrid realizes what he's done and rushes to his side, crying and begging him not to leave, would be extremely sad.
Perhaps in the fanfiction, Hiccup has been poisoned and he's slowly dying. As he's dying, he gives Astrid his most prized possession, like a dragon - related item that has been with him through all his adventures. He tells her to keep it as a reminder of him. Astrid is left holding this item, watching Hiccup slip away, and the sense of finality and loss is what makes it a heartbreaking scene.
Astrid might initially be in shock. She could just stand there, frozen, unable to believe that Hiccup is really gone. Her eyes wide open and her body trembling as she tries to process what has just happened.
Hiccup would probably be very worried. He'd rush to her side immediately. He might start to check her injuries right away and call for help if needed.
It develops gradually. At first, they might be just friends who respect each other's skills. But as they go on more adventures together, they start to notice little things about each other. For example, Hiccup notices how Astrid is always the first to volunteer for dangerous tasks because of her bravery. And Astrid sees how Hiccup's intelligence always gets them out of tough situations.
In the fanfiction, perhaps there's a moment when Hiccup gets injured while protecting the village. Astrid stays by his side day and night, taking care of him. She reads to him, makes him his favorite food, and in those quiet days, they realize how much they mean to each other. Their love deepens as they share these tender moments.
In a fight before she dies, Max could be protecting someone she cares about deeply. As she takes the fatal blow, the look on her face as she realizes she can't be there for that person anymore would be extremely sad. And the person she was protecting would be left with a sense of guilt and loss.
One heartbreaking scene could be when Red's Pokémon try to revive him but fail. They use all their strength and abilities, but it's just not enough. Another might be when his friends gather around his lifeless body, reminiscing about all their adventures together.
In some fanfictions, Castiel dies protecting a whole town. He uses all his power to create a shield against a dark force. As he does this, he can feel his life draining away. The townspeople watch in horror as he falls to the ground, his wings burning out behind him. His last words are of hope for the future and forgiveness for his enemies. This kind of scene is really sad because it shows his selfless nature even at the cost of his life.
One possible fanfiction could be about how Hiccup and Astrid deal with the pregnancy. Hiccup might be overprotective, constantly worried about Astrid and the baby. Meanwhile, Astrid could be trying to keep up with her normal Viking duties while also preparing for motherhood. And the lemon element could be a symbol in the story, perhaps it's something Astrid craves during her pregnancy, leading to some humorous or heartwarming scenes between her and Hiccup as he tries to find the perfect lemon for her.
Their relationship might become more equal in some ways. As dragons, they are both facing a new and strange existence, so they have to rely on each other more. They might develop a new understanding of each other's strengths and weaknesses.
One of the most heartbreaking scenes could be when his friends find out about Naruto's death. For example, Sakura, who has been with Naruto through so much, would be completely shattered. Her reaction of disbelief and then overwhelming grief would be really sad. Another scene might be when the whole village of Konoha hears the news. The silence that would fall over the village, with people just stopping in their tracks, would be a very poignant moment.