Resolve
After discovering Shizuka was one of the casualties during the battle, Nagate recounts the events and what ensued during the fight: Multiple squads of frames are deployed to destroy the Guana with Kunato's squad tasked to destroy the tail of the massive Gauna using explosives. Kunato, Shizuka, En and Nagate plant their explosives around the tail of the Guana and prepare to detonate on Kunato's orders. Kunato however, activates a secure channel with Nagate and deliberately orders him to detonate the explosives too soon. This causes the Guana to become aware of their plans and the other explosives are shaken loose due to the imbalanced explosion. All frames are then ordered to temporarily fall back and re group but Nagate loses confidence and is struck by the tail. As Nagate begins to fall unconscious, the Guana almost kills him but Shizuka saves him at the expense of her own life. In the present, Nagate has recovered from his injuries but is greatly hated by the population as they believe he was the cause for many deaths during the battle (Due to the tail not being severed). Nagate takes some time away with Izana and he slowly regains his confidence in piloting Tsugumori. Meanwhile the captain orders the destruction of a Gas giant as it is believed there are Gauna present on the planet. With Yuhata assisting the captain the planet is destroyed successfully but 3 unidentified Guana appear from the planet. The Captain orders Yuhata to assemble some pilots (Including Nagate) to intercept and destroy the Guana. When more detailed images of the Guana are shown, it is revealed, to the shock of everyone, they are Gauna like replicas of the a guardian frame with tag number 702 which was the same frame Shizuka used in battle.
Aired 23/05/2014EP 7 - Resolve

Knights of Sidonia
It's been a thousand years since the Gauna, a strange alien race with no known method of communication, destroyed the solar system. A portion of humanity managed to escape using enormous "seed ships" like the Sidonia, which have allowed them to maintain the population while drifting through space. Nagate Tanikaze is a young man who has been raised deep in the bowels of the ship. When he goes into training to pilot the huge robotic weapons known as Gardes, Nagate is entrusted with piloting the legendary unit known as Tsugumori. Nagate and his fellow pilots put their lives on the line against the Gauna, in the ultimate battle for the survival of humanity!
(Source: AniDB)