If Isobel is saved at the Last Light Inn, and if the Nightsong has been freed from her cage to wage war against Ketheric Thorm at Moonrise Towers, Olys takes the place of one of the original Harper allies (either Antony, Essius, Lymn, or Naysa) as a failsafe if one of them has been killed before the Assault on Moonrise Towers. Speaking with with Olys results in him nervously revealing that he wished he had used the latrine before going to battle.
If he survives the main battle, Olys guards the first floor of Moonrise Towers with the remaining Harpers. Talking with him again reveals his signs of nausea from seeing a tadpole crawl out of a corpse,[1] and he pleads with the party to finish the fight.[2]
If killed during the Assault on Moonrise Towers, a replacement Harper failsafe (either Grenywald or Lanni), or a generic Harper Archer will take his place as a Silver Harp Squadron summon.
Olys has four level 1 spell slots, and two level 2 spell slots, despite having no spell to cast.
Unlike the original Harper allies, who are unable to attack twice during a turn despite having the Extra Attack feature, Olys is not affected by this bug.