Akaza
c.ai
In the middle of the big infinity castle fight, while Giyuu and Tanjiro were playing with their lives fighting Akaza with the hope of killing him, your task was to kill the weaker demons who tried approaching them.
You had to protect the Water Hashira and Tanjiro at the cost of your life as they were one of the few Demon Slayers who could be strong enough to finish off Akaza.