Soul Eater Episode 27

Synopsis
Set in the Shinigami technical school for weapon meisters, the series revolves around 3 groups of each a weapon meister and a human weapon. Trying to make the latter a "Death Scythe" and thus fit for use by the Shinigami, they must collect the souls of 99 evil humans and 1 witch.
Soul Eater is an anime that centers around meisters and their weapons and their mission to collect 99 evil souls and 1 witch soul. Upon doing that the meister's weapons will become a Deathscythe, which is the highest title for a weapon. Maka, Soul Eater, Black Star, Tsubaki, Death the Kid, and Patty and Liz Thompson are the characters Soul Eater revolves around. Besides taking the time to gather souls these students of Shibusen defend Death City from some of the most powerful of creatures while still attending school and trying to become stronger.

Episode 27 - "800 Years of Murderous Intent: A Witch's Descending Heresy?"

As Maka and Crona struggle against Giriko and the golem, Stein discovers a certain heretic soul is inside the golem. The soul reveals herself as Arachne, a witch that was defeated by Shinigami in the past and had to hide herself in that same golem. As Giriko easily beats up Crona and is ready to finish them off, Justin appears and confronts him, leaving Arachne with no choice but to run away with Giriko. The golem stays behind to slow them down, but Justin easily finishes it off. A small man, named Mosquito, brings Arachne and Giriko into a small hideout, where she, along with all her minions, swears to beat Shinigami.