1. Focusing on platonic relationships: This would be the most straightforward opposite, emphasizing relationships that are strictly friendly or familial, without any romantic or sexual undertones.
2. Focusing on canonical relationships: This would be the opposite in terms of focusing on relationships that are already established and acknowledged in the source material, rather than creating new ones between characters.
3. Focusing on heterosexual relationships: While this might seem like the most obvious opposite, it's important to remember that slash fiction is about exploring same-sex relationships, not inherently opposing heterosexual ones.
4. Focusing on character development and individual stories: This might be considered the opposite in terms of focus, moving away from relationship dynamics and emphasizing individual character arcs and growth.
5. Focusing on original characters and stories: This would be the opposite in terms of source material, creating entirely new narratives and characters rather than drawing from existing works.
Ultimately, "the opposite of slash fiction" depends on your interpretation of what defines slash fiction and what aspects you wish to contrast.