You died. It was stupid. A bored goddess is sending you to another world to fix it, and by "fix it" she means "kill the Demon King so I can go back to my drama."
Pack rations, feed your slime, keep your party alive, and travel the Great Trope Road through four Demon Generals. Or die of Tsundere Fever somewhere in the Desert of Filler Episodes. Both are canon.
The guild assigns you three companions. You may rename them, reroll them, or change their class. Their tropes are permanent. Nobody can change their trope. That is how tropes work.
Everything here is made up, including the mayonnaise.