Zead

Zead is a main villain who works with Isaac in Castlevania: Curse of Darkness. A priest who claims to seek the end of the curse and gives Hector clues as to Isaac's whereabouts. His true identity is Death.

Official background: A man that seeks to abolish the curse that is afflicting Europe. He wishes for Isaac to be vanquished so that the curse may finally be lifted. He constantly supplies Hector with information about Isaac and his whereabouts.

Zead appears as a priest, who investigates the source of the curse that runs through Europe. Hector encounters him a few times, one of which reveals that he seems to have a grudge against Saint Germain. Eventually, although not directly stated, Zead manages to lock Saint Germain at the top of the clock tower in the Eneomaos Machine Tower, where he planned to make Hector and Saint Germain kill each other; however, neither of them die and they are released from said place. It is here where Hector questions his ideals of revenge towards Isaac, thereby preventing him from becoming the next host for Lord Dracula.

After Isaac's defeat, Zead reveals that he is actually Death in disguise. When Hector refuses to let the curse consume him, Zead applauds Hector's strength of will before assuming his true form and engaging the Devil Forgemaster in battle.

Name Speculation
There is a point that should give him away who he is actually, despite Hector's unawareness. Zead is an anagram of Deaz or THE AD, which is similiar the way that most monster encyclopedias in past games call death (デス). This might give the player an idea who he actually is.