A skilled athlete in her own right, Otonashi Saya fights using a special katana with an edge she can touch with her thumb while gripping it so that she can draw blood. The grooves are specially designed to spread her blood through the entire length of its blade. Once it’s coated with her blood, it becomes a deadly weapon against Diva and any chiropteran created from Diva’s blood.
This cosplayer is a little scary too. I wonder if all Saya cosplayers are like this? Thanks again to Harrell for sending this in!
EDIT: Thanks to Syaza for letting me know this is Lenneth XVII!