Theotar, the Mad Duke is a legendary neutral minion card that belongs to the "Murder at Castle Nathria" set, which was released on 02.08.2022 and is one of initially 135 cards. The artist of this card was Arthur Bozonnet, who also made 110 other artworks for Hearthstone.
The flavor text of the card is the following: "I'm afraid you've gone mad! You're entirely bonkers. But I'll tell you a secret. All the best souls are."
The card is easy to memorize with 97.62% of correct quiz questions.