Person

A self-conscious or rational being;
About the girl who cosplays

Personification

The representation of a thing or abstraction in the form of a person;
About the act of cosplay; a collection of related articles

Personas

An actor's portrayal of someone in a play;
About the characters and costumes

Period

A completion or conclusion;
Before you leave: Links; Tagboard

Persona

Narushige Shigeka (重華 成重)

Narushige Shigeka from the manga

About the character : Silver Diamond (シルバーダイヤモンド)

Why him? :

About the costume :

Picture credits : Reference pictures taken from MangaFox.