Jacob Staalek

Jacob Staalek is a youth unsure of his path in life. Tyrael regarded him as "a mortal of incredible resolve and virtue."

Sword of Justice
Jacob was a native of Staalbreak, and the son of the city's constable. Jacob and his father crossed swords and in the fray, his father was killed. He fled to Lut Gholein, charged with murder. Hunted by his kinsmen, including a childhood friend, Jacob met a seer in the city. Following the prophet's visions, Jacob came to a cave at the base of what was left of Mount Arreat. There, he found El'druin, blade of the archangel Tyrael. Taking up the sword, he was charged with ridding the Dreadlands of a plague that was corrupting his countrymen. To this end, he allied with the wizard Shanar.

Sometime after his adventure, word of Jacob's deeds reached the ears of Deckard Cain, and he expressed interest in writing more on the hero. However, the scholar was killed before this could come to pass.

Storm of Light
Following Tyrael's reformation twenty years after he was seemingly destroyed at Mount Arreat, El'druin returned to him leaving Jacob's possession. The sudden disappearance of El'druin devastated Jacob. Without its power and guidance he was no longer the avatar of justice he once was. The loss of El'druin was followed by a second, possibly greater one, as Shanar left Jacob soon after. Jacob fell into depression after this, and began wandering Sanctuary.

After the defeat of Diablo by the Nephalem, Jacob found himself in Caldeum. Following a mention of El'druin's whereabouts Jacob stumbled into a trap set by a demon out for revenge. Fighting the demon he slew a few of its cultist minions but was helpless without El'druin. He was saved by Shanar, who foresaw this event, killing the demon and cultists. Jacob then accompanied her to journey to New Tristriam. He came to be recruited into the newly reformed Horadrim by Tyrael

In-game
It was stated that Jacob would appear as an NPC in Diablo Immortal. By this point he was wielding El'druin. However, he makes no appearance in the final game.