Upon hearing these words, Leonard Churchill and the others received an enlightenment altogether, "Triggered team-shared Grade B hidden plot; investigate the secret behind 'Poison Sting' Taylor's resurrection at Black Crow Fort..."
Now everyone understood.
Just after Sack's team had entered, they had encountered a suspicious bandit and killed him. To their surprise, "he" came back to life. Due to their carelessness, they lost a knight.
The monster wasn't strong; it was an ambush, negligence was to blame.
And the resurrected monster, seeing that it was no match, ran away.
It was the dark shadow that Leonard and his team saw rapidly fleeing through the tree canopy when they arrived.
Such an absurd plot similarly furrowed the brows of both Serli's group and Sack's group.
However, Leonard had entirely figured it out, and he reached a conclusion that startled even himself, "Vampire!"
...
Leonard and his party were listening to the guard narrating what had just happened.