Is it correct that Yellowfang her proper name after joining ThunderClan? If so, why was she allowed to have a name that didn't match her appearance and skills? Was it technically an injury name, legally? Wouldn't it be clan policy to make incomers pick a name that matches and just have a favored nickname?
Yellowfang is an unusual case in a lot of regards, but the main reason she chose that name was to completely shed her old life and devote herself to ThunderClan via a nickname that members of the Clan had already given her. It is technically an injury name - her teeth were very fucked up, and she was using a literal -fang rather than the skill suffix of -fang - but moreso it was her way of declaring herself part of ThunderClan.
I'm sure that someone like Leopardstar would have insisted that she be named something normal and legal, but the gesture of accepting a nickname given to her by her new home was the right call. ThunderClan took a much bigger liking to her after that.
