Title

Character titles are included in the game code in the Diablo III beta. It's not known how or when these titles will be applied in the full game, or if the numbers correspond directly to Character levels. The developers have said they like the idea of titles for characters, but there's no final word on the feature.

Titles are appended before the character name.

Diablo III Character Titles=

These titles refer to a level, but it's not clear if that's a character level, or some other sort of ranking or achievement.

There are not different titles for Hardcore and Softcore

The maximum level in vanilla Diablo III is 60. This list of titles might include additional ranks to be added in the expansion(s) packs, but that is unconfirmed.

Level 10: Sir / Dame
Level 15: Baron / Baroness
Level 20: Count / Countess
Level 25: Duke / Duchess
Level 30: Lord / Lady
Level 40: King / Queen
Level 50: Defender / Defender
Level 60: Champion / Champion
Level 70: Guardian / Guardian
Level 80: Conqueror / Conqueror
Level 90: Destroyer / Destroyer
Level 100: Avenger / Avenger
Level Max: Patriarch / Matriarch

Diablo II Character Titles

Titles were earned for completing each difficulty level in Diablo II, without any connection to a character's level. There were different titles for Hardcore and Softcore, and new titles were added in the expansion pack.

Normal (softcore) character titles:

Normal Difficulty: Sir, Dame
Nightmare Difficulty: Lord, Lady
Hell Difficulty: Baron, Baroness

Hardcore character titles:

Normal Difficulty: Count, Countess
Nightmare Difficulty: Duke, Duchess
Hell Difficulty: King, Queen

Diablo II: Lord of Destruction Titles