Jentulf

Royal Apothecary Jentulf was a prodigious, eccentric potion maker in service of Justinian IV.

Bounties
As an assistant apothecary of Westmarch, in 1270, Jentulf offered a number of bounties to adventurers.

Jentulf heard of the Countess, and how she had been resurrected in a blood ritual. Wishing to learn more about her and her methods, he requested that adventurers retrieve some of her blood. He was willing to pay well for even a single drop of it.

He also requested that venom be delivered to him from the fangs of Toxic Lurkers, promising payment upon delivery.

Royal Apothecary
Later, Jentulf was a leading apothecary at the royal court, crafting potions to enhance the king's army, as a member of His Majesty's war council. He did so in a very controversial manner, however. Apparently, he himself did not fully realize exactly how his potions worked, yet was sure of being the greatest apothecary of his time. He was known to draw ideas from others sometimes, putting them to effective use.

After making a potion that allowed the taking life of the slain for oneself, he promptly tested it by committing murder. Jentulf was put to trial afterwards and sentenced to imprisonment. The apothecary genuinely did not understand what did he do wrong, accusing the judges of being simply jealous. In prison, stripped of his title, he pleaded the king for early release, promising to create more invigorating potions. Later, Jentulf was granted freedom and reinstated. However, he became more sinister afterwards, believing that fear is the greatest motivation, which reflected on his new creations. His contempt towards the other apothecaries grew greatly, as Jentulf believed they all expected him to lose his talent during imprisonment. In the end, Jentulf disappeared without a trace, stating in his final letter that his genius transcended benevolence and embraced chaos.

Diablo Immortal
Jentulf is referenced in Diablo Immortal, as the provider of the "Blood of the Countess" and "Arach Venom" bounties.

Diablo III
Jentulf is first referenced in Diablo III. Here, his Legendary Potions can be obtained as in-game items, each of them (except Bottomless Potion of Kulle-Aid and Bottomless Potion of the Unfettered) telling a part of Jentulf's story.

Trivia

 * The king Jentulf serves goes unnamed in Diablo III (not to mention its court and country), but in Diablo Immortal, it is strongly implied to be the King of Westmarch. Given the timeframe of the game, and how the events described in the Diablo III text must come after it, the king he serves has to be Justinian IV.