Decus is a member of the Vanguard who fights using a broad sword. Many of Decus attacks are German words, even his name is German. The leader of the Vanguard entrusts Decus with a cenutrions core that grants him a special ability. Decus is madly in love with Alice and will do anything she wishes though she doesn't appear to share the same feelings. You can find out more about their relationship by doing the Alice Sidequest.
Decus's special ability grants him the ability to change forms and look like anyone else. He uses this ability to transform into Lloyd and attack Palmacosta. This is the reason for Emil's hatred toward Lloyd though it was actually Decus. After the collapse of the Vanguard, Alice and Decus begin working with Richter in order to gain power. In the final dungeon you must fight Alice and Decus and after beating them there is a cut scene where Decus throws himself in front of Alice to save her life and just before he dies she reveals that she loved him and then she to gets killed.
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