Frieren: Beyond Journey's End, Vol. 14 (manga)

At the behest of the Continental Magic Association, Frieren and her friends are in the Imperial capital to stop a plot to assassinate the great mage Serie. Frieren must contend with the Magic Special Forces on one side and a cabal of assassins known as the Shadow Warriors on the other. The hit is scheduled to take place at a grand ball, but before that happens the Shadow Warriors will make their move to take out Frieren in the streets of the city...