A good way to know is by looking at the writing style. Clear, vivid language and a smooth flow usually indicate a good short story. Also, if it leaves you thinking or feeling something long after you've finished reading, that's a sign it's a good one.
You can tell if it's a short story by looking at its length. If it's relatively brief and focuses on a single incident or a limited set of characters and events, it's likely a short story.
You could know the short story by discussing it with others who have read it or reading reviews and critiques. That way, you can gain different perspectives and insights.
One of the main themes is power and its implications. The Iceblade Sorcerer's journey towards ruling the world likely involves his acquisition and mastery of power. Another theme could be identity, as he discovers who he is in the context of his great power. There may also be themes of friendship and loyalty as he likely has allies on his path.
The Iceblade Sorcerer is the central figure, of course. But there may be friends or comrades who stand by his side. These characters could provide emotional support or strategic help. And don't forget about the antagonists. They could be powerful sorcerers or those in positions of political power who don't want him to rule.
A Konan and Pain fanfic could explore their unique relationship within the Akatsuki. It might focus on their shared goals and how they interact on missions. For example, a story could show Pain's philosophical views influencing Konan's actions, and vice versa.
I'm not entirely sure about the exact main plot of the 'iceblade sorcerer shall rule the world light novel'. But from the title, we can assume that the protagonist, the iceblade sorcerer, is on a quest for world domination. There could be a complex backstory about how they got their powers, perhaps they were an outcast or had a special destiny. They might encounter other sorcerers with different powers who either oppose or support them. And the world they live in could be full of magic, mystery, and different factions vying for control. The story could also explore themes of power, morality, and what it really means to rule the world.
In this fanfic, it might also re - imagine the battles involving Pain. Instead of the battles being just about physical combat, it could explore the psychological warfare aspect more. Pain's abilities, like the Six Paths of Pain, could be used in more creative ways to create a more engaging and different story. It could also focus on how the other characters in Naruto try to understand and counter Pain's complex ideology while dealing with the destruction he causes.