Well, it could be really interesting. Some characters might be amused by the different interpretations of their world in the fanfiction. They might find some of the ideas creative and enjoy seeing how fans view their relationships and adventures. For example, the Goblin Slayer himself might be surprised at how fans depict his internal thoughts in the fan - made stories.
The characters could have mixed feelings. They might appreciate the creativity of the fans in some cases. For instance, if a fanfiction delves deeper into a relationship between two characters in a way that makes sense, they could be happy about it. But if the fanfiction goes against their values or misrepresents them, they would be unhappy. Take the Goblin Slayer, he values his mission above all, if a fanfiction makes it seem like he doesn't, he would be displeased.
The Priestess is an obvious one. She has already shown admiration and a certain closeness to the Goblin Slayer in the original story. Then there could be a female knight who is impressed by his combat abilities against goblins. Also, an adventurer girl who is new to the goblin - slaying business and looks up to him as a mentor could be part of it.
Yes, there are likely some Naruto is Goblin Slayer fanfictions out there. Fanfiction writers often like to combine different popular franchises in creative ways. You can try searching on popular fanfiction websites like FanFiction.net or Archive of Our Own.
One interesting aspect could be the contrast in their fighting styles. The Goblin Slayer is more methodical and strategic when dealing with goblins, using his knowledge of their habits. The Doom Slayer, on the other hand, is a force of pure destruction. In a crossover, perhaps they could learn from each other. The Goblin Slayer could pick up some of the Doom Slayer's more aggressive tactics, while the Doom Slayer might gain some strategic thinking from the Goblin Slayer.
Goblin Slayer is of course a very important character. He is the main protagonist focused on slaying goblins. Priestess is another important one. She often accompanies Goblin Slayer on his missions and uses her healing and support magic. High Elf Archer is also significant. She provides ranged combat support in battles against goblins. Dwarf Shaman helps with his knowledge of magic related to earth and such elements which are useful in combat situations against goblins.
The Goblin Slayer would likely first have to adapt to the new technology. He'd be cautious around blasters and lightsabers, but would quickly realize their potential in combat. He might start by observing how others use these weapons and then find ways to incorporate them into his own fighting style. For example, he could attach a blaster to his existing weaponry for ranged attacks. In terms of the setting, he'd have to get used to different planets and their unique environments. He'd probably study the local flora and fauna to see if there are any new threats or resources he can use, just as he does in his own world.
If it's a crossover with 'Naruto', Naruto Uzumaki would be an interesting character to pair with the Goblin Slayer. Naruto's positive attitude and his powerful ninja skills could complement the Goblin Slayer's more serious and direct fighting style. They could work together to protect a village that is being attacked by goblins. Also, in a crossover with 'One Piece', Luffy could be paired with the Goblin Slayer. Luffy's determination and his ability to lead his crew could be useful when they are facing a large group of goblins.
Obviously, the Goblin Slayer himself would be one of the main characters. From Destiny, the Guardian, especially a Hunter with their stealth and agility, could be a great match. The Hunter's ability to quickly dispatch enemies and traverse difficult terrain could complement the Goblin Slayer's more brute - force approach when it comes to goblin - slaying.
In many Goblin Slayer fanfictions, the female knight often represents a symbol of courage. She might be depicted as having unique combat skills, perhaps trained in a different style compared to Goblin Slayer. For example, she could be more versed in swordsmanship with a touch of elegance, while Goblin Slayer is known for his brutal and effective methods. Her character can also bring a different dynamic to the group, adding a bit of a chivalrous aspect to their adventures.