Lost in the Cruel World (Visual Novel)

Lost in the Cruel World is a visual novel by Hiroshi Seko. It was first released on September 18th, 2013 in Japan bundled with the third anime Blu-ray. The story was also included in the novel Attack on Titan: Lost Girls which was later adapted into a manga of the same name.

Part One
During the battle of Trost District, Armin Arlert informs Mikasa Ackerman that Eren Yeager has been killed in battle alongside his comrades. With a lost sense of purpose, Mikasa speeds through the city killing Titans until her Vertical Maneuvering Equipment runs out of gas, sending her falling to the ground below.

As she lies in a daze, having fallen onto a shop awning, Mikasa is filled with regret at her inability to save Eren and distaste at the biting cold brought by a light rainfall. Looking up at the gray sky, she sees a white butterfly fluttering across the battlefield. She grows upset, blaming the rain for the tragedy of that day since hardships in her life have always been accompanied by rain. Before her grief can consume her, she stops herself from thinking.