He journeyed into the barrows in search of the Sapphire Dragon Claw. As he wanted to stay within the barrows, he fooled the villagers into believing the Barrows was haunted by rattling some pots to scare them away. The Barrow's "haunted" reputation gave Wyndelius an idea to create a potion that would make him appear like a ghost, and further used this to continue to frighten the villagers. However, he soon grew mad, possibly as a side effect of the potion, and eventually began believing that he was the guardian of the barrow.
In Ivarstead, the Dragonborn is given a quest to investigate a haunting in the Shroud Hearth Barrow. Upon investigating the Barrow, they encounter Wyndelius on the other side of a gate, who appears "ghostly" due to the potion's effects, and he warns the Dragonborn to leave at once.
- If Wyndelius is resurrected with the Dead Thrall spell, he will be resurrected as his "ghostly" form. He also does not use the standard groans of most other reanimated dead, but will instead use the unique dialogue that he had in life.
- His journal indicates that he has gone insane, either as a result of using the potion, or, as he writes, by his frustration at being unable to find the Sapphire Dragon Claw. It is also possible that he has been possessed by the Guardian of Shroud Hearth Barrow, as the final date of 1E 1050 is so far in the past.
- When first encountering him (when he appears in spectral form and warns the Dragonborn to leave), if he catches the Dragonborn pickpocketing him through the gate, he will immediately teleport around the corner to his living area.
- It is possible to kill Wyndelius when he is first met, by using ranged weapon or magic and shooting through the gate.
- It is possible to clear the barrow without killing Wyndelius.
- If Wyndelius is left alive, the Dragonborn can hear him comment "Is there Living among the dead? The life has vanished," while walking through the passageway leading to his room.
- When Wyndelius dies, an effect that looks like the animation of Rally appears. This also happens when he is raised via Dead Thrall and killed again.