I'm not sure specifically which 'A Sad Eevees Story' you mean. It could be about an Eevee in a Pokémon world that has lost its trainer, or maybe it was bullied by other Pokémon. Without more details, it's hard to say exactly.
Yes, in some ways life can be a sad story. There are often hardships, losses, and disappointments. People face the death of loved ones, failed dreams, and difficult circumstances. For example, a person who has been through a long battle with illness and watched their health deteriorate might feel that life is a sad story. But it's also important to note that there are also moments of joy and beauty that can temper this view.
Since it's a fanfic about two Eevees, it might revolve around their evolution. Perhaps one Eevee has a strong desire to evolve into a certain form, like a Vaporeon because it loves the water, while the other Eevee is content with being just an Eevee for a while. The story could detail their journey towards or away from evolution. It could also include elements of the Pokemon world such as trainers, battles, and the search for rare items. There might be conflicts like rivalries with other Pokemon or misunderstandings between the two Eevees that they need to overcome.
Wolves in beta might face various challenges. Maybe they are in a new or restricted environment. For example, they could have less territory to roam compared to their natural habitats. This would limit their hunting grounds and thus make it harder for them to find enough food. Their social structure could also be disrupted, as they might not be able to form packs as freely as in the wild. This could lead to loneliness and a sense of insecurity among the wolves.
A sad Gacha Life story could be about a character who loses their best friend in the game. For example, they might have planned to build a virtual world together, but then the friend quits playing. It makes the remaining character feel lonely and sad.
Once in Gacha Life, there was a character named Lily. She was always left out by the other characters in the club. They would go on adventures and have parties, but never invited her. Lily would sit alone in the corner of the virtual schoolyard, feeling so sad and unwanted. It made her virtual heart break every day.
Given that it's 'a tale of two eevees fanfic', the two Eevees are probably the main characters. However, there could also be other Pokemon or trainers that play significant roles in the story. Maybe there's a friendly Pikachu that helps the Eevees out in times of trouble, or a strict trainer who has an influence on their development.