From Diablo Wiki

Titles are earned by defeating the game on each difficulty level (Normal, Nightmare and Hell). This means killing Diablo in Diablo II (D2C, or D2 classic), and killing Baal in Diablo II: Lord of Destruction (D2X, or D2 Expansion).

Diablo II Titles [ edit ]

Normal softcore [ edit ]

Normal (softcore) character titles:

Normal Difficulty: Sir, Dame

Nightmare Difficulty: Lord, Lady

Hell Difficulty: Baron, Baroness

Normal hardcore [ edit ]

Hardcore character titles:

Normal Difficulty: Count, Countess

Nightmare Difficulty: Duke, Duchess

Hell Difficulty: King, Queen

Diablo II: Lord of Destruction Titles [ edit ]

Expansion softcore [ edit ]

Normal (softcore) character titles:

Normal Difficulty: Slayer

Nightmare Difficulty: Champion

Hell Difficulty: Patriarch, Matriarch

Expansion hardcore [ edit ]

Hardcore character titles: