Weiß Kreuz (ヴァイスクロイツ Vaisu Kuroitsu, German for "white cross"), released in the United States as Knight Hunters, is an anime about four assassins that work in a flower shop. The assassins are members of a group called Weiß (white), which is run by the mysterious Persia. The members of Weiß are:

• Aya, a man whose sister is in a mysterious coma
• Omi, a boy who doesn't know his past
• Ken, an ex-professional soccer player
• Youji, a womanizer.

Together they fight the evildoers.

The enemies in the series are another group of assassins called Schwarz (black). Schwarz work as bodyguards for the evil Takatori. Each of the four members of Schwarz has a special power: Crawford possesses precognition, Schuldig is a telepath, Nagi is telekinetic, and Farfarello cannot feel any pain. Later in the series, Schwarz is seen assisting a mysterious group known as "Eszet" (spoken word for german alphabetic character "ß") in resurrecting their deceased leader.

There is a second series, called "Weiß Kreuz Glühen," (white cross glowing) which is set after the first. Several of the original Weiß members are not immediately visible; two new ones are introduced in the first episode (Sena and Kyo). Glühen takes place at Koua Academy, and it spans 13 episodes. In terms of the animation quality, it's quite a bit nicer; however, the character design is vastly different due to legal disputes with the original character designer.

Schwarz also appears in Glühen; they also have changed appearances due to the lawsuit.

This series is a favorite of shōnen-ai and yaoi lovers, due to the primarily male cast, and the fact that each member of Weiß has a specific flower assigned to them.