One possible plot could be that the Doom Slayer somehow gets transported to the world of Goblin Slayer. He then uses his advanced weaponry and combat skills to help the Goblin Slayer in his never - ending fight against the goblins. Maybe they team up to take on a super - powerful goblin boss that neither could defeat alone.
I think the Doom Slayer would be more dominant. His suit gives him enhanced strength, speed, and durability. He has weapons that can level entire areas. While the Goblin Slayer is highly skilled at what he does, the Doom Slayer has fought on a much larger scale against far more dangerous foes. His presence alone would probably intimidate most of the goblins, and his ability to take on hordes of enemies without flinching makes him a very dominant force in any encounter.
There are definitely some 'Goblin Slayer x Doom' fanfics. One interesting aspect that some of these fanfics explore is the different combat styles of the two main characters. The Goblin Slayer is more methodical in his approach to dealing with goblins, while the Doomguy is all about brute force against demons. In a crossover fanfic, seeing how they would either learn from each other or clash because of their different styles can be really engaging. Also, the settings of the two can be blended in unique ways, like the dark and gritty world of 'Doom' with the medieval - ish setting of 'Goblin Slayer'.
Well, the plot could involve a rift opening between the two worlds. Goblins start pouring into the Doom world and the Doomguy has to deal with them. Meanwhile, the Goblin Slayer follows the goblins through the rift and they end up working together to close the rift and stop the chaos. They might exchange combat techniques and learn from each other's experiences along the way.
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.
There could be a cultural clash. The Doom Slayer comes from a more futuristic and hellish setting, while the Goblin Slayer is in a medieval - ish fantasy world. Their ways of communicating and understanding the world are different. However, this could also lead to some interesting exchanges. For example, the Goblin Slayer might be fascinated by the Doom Slayer's energy - based weapons, and the Doom Slayer could be intrigued by the magic and alchemy in the Goblin Slayer's world.
One possible plot could be that the Doom Slayer is somehow transported to the world of Goblin Slayer. He then teams up with Goblin Slayer to take on an especially powerful horde of goblins that have been corrupted by demonic forces from Doom. Their combined skills in combat, the Doom Slayer's superhuman strength and arsenal, and Goblin Slayer's knowledge of goblin tactics would make for an epic battle.
One idea could be a crossover with 'Sword Art Online'. The Goblin Slayer could be transported into the virtual world of SAO where he has to deal with goblin - like mobs in a different gaming environment. He might use his unique skills and no - nonsense attitude to clear floors and quests in the game.
It could be a powerful demon lord from the Doom universe that has possessed a goblin king in the Goblin Slayer world. This combined entity would have the cunning and numbers of the goblins along with the raw power and dark magic of the demon lord. It would be a formidable foe for the Doom Slayer and Goblin Slayer to face.