Aegis D. Crown

Aegis D. Crown (エイジス D. クラウン Eijisu Dī Kuraun) is the 5th King of Crown (第５代 冠国の王 Dai Sandai Kankoku no Ō)

He is the son of Argus D. Crown. He is also the adoptive son of Eriza, who also preceded the throne.

Devil Fruit
Aegis has eaten the Gira Gira no Mi (ギラギラの実), a Paramecia-class Devil Fruit that allows him to turn into diamond, making him a Diamond Human (ダイヤモンド人間 Daiyamondo Ningen). Gira Gira (ぎらぎら) is an onomatopoeia for sparkling or glittering.

Etymology
Aegis (Αἰγίς) is a shield in Greek mythology, and is taken to mean "the protection, backing, or support of a particular person or organization" in modern context. In other words, Aegis is a person who will protect those important to him, and is why he was given the Gira Gira no Mi.