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Names to Run Away from Really Fast when this is part of an earned reputation as The Dreaded
Names to Trust Immediately for the positive counterpart (Say, the city gate is guarded by the Gentle Giant knight Bartholomew The Steadfast)
Nom de Guerre can overlap with some of these, like the various pirates in One Piece often having a Freeze-Frame Introduction-style Name:Descriptive Nickname
I was wondering if a trope page exists for something like this? This exists outside of anime, but is pretty common specifically in anime. Either for titles associated as a group, or for an individual. I think the character doesn't specifically need to be incredibly powerful to fit into this trope, just that they actually have a title, but obviously it's more common for a powerful character to be given a title. Here are some examples:
One Piece: - World's Greatest Swordsman - The Strongest Creature - Shikibukai (Seven Warlords of the Sea) - Yonko (Four Emporers)
Toriko: - The Four Heavenly Kings - Gourmet Human National Treasures - "Knocking" Master
Feng Shen Ji: - Greatest Swordsman Under Heaven - Great Generals of the Dark Ones
Bleach: - Captains of the Gotei 13
God of Highschool: - The Six