Octavia and the others didn’t remain idle during the whole duration of the fight. In fact, as soon as the first explosion came about, they woke up instantly. After all, there probably wouldn’t be anyone who could stay asleep with the amount of commotion that Asther made.
This is also part of the reason why Asther started of the attack in that way. He wanted them to wake up because, through this, he wouldn’t need to worry about them getting killed or kidn*pped in their sleep.
However, as for the action itself, the group didn’t get to do any fighting at all. When they arrived at the scene of the battle, there isn’t anyone left for them to fight anymore. Asther and his undead have taken care of all the mercenaries.
[You have cleared the first Sub Quest!]
“Alright. Two left.” Asther said a
