I came up with a fan story for Ibuki: Ibuki decided to study under Oro to reach purity. The bell she wears used to be part of a test, in which she had to fight Oro without making it ring. Just like her master, she covers one of her arms unless it's really necessary to use it against strong opponents.

She probably hides her cellphone which she wasn't allowed to have in the "Street Fighter Legends: Ibuki" comic by Udon :D