Kunzite

Kunzite is the fourth and most powerful general of Queen Beryl. He was originally a general to Prince Endymion.

Appearance
Kunzite has long white hair. He wears a white suit and gloves and a cape. He is the tallest of the Shitennou, and his estimated age is 25-26, as stated in the Materials Collection.

Codename Sailor V
While he didn't directly act against Minako during her battle against the Dark Agency, he was stated as being the superior of the Dark Agency's leader, Ace Kaitou a.k.a. Danburite.

Pretty Soldier Sailor Moon
Kunzite is the last of the Shitennou to appear, and he is also the most powerful. He is the commander of the Middle Eastern division of the Dark Kingdom, and initially appears after Nephrite's death as a mentor to Zoisite. He advises Zoisite to be careful, and to think his plans through properly.

After Zoisite's failure and subsequent death, he is left alone to fight against the Senshi. He is determined to locate the Silver Crystal, but feels that he must kill the Sailor Senshi and the Moon Princess first. In Act 9 - Serenity, Princess he lures the Senshi to the top of Tokyo Tower to battle. This ultimately culminates in Tuxedo Mask taking a hit for Sailor Moon, who then awakens as Princess Serenity of the Moon Kingdom. The Silver Crystal appears after forming from one of Serenity's tears, and eminates a light that allows Kunzite to remember his past as a knight to Prince Endymion.

Trivia

 * Kunzite's name is likely derived from a variety of spodumene known as Kunzite.