

Summer Time Rendering ( サマータイムレンダ, Samā Taimu Renda) (2022) (screenwriter).

The Idaten Deities Know Only Peace ( 平穏世代の韋駄天達, Heion Sedai no Idaten-tachi) (2021) (screenwriter).Dorohedoro ( ドロヘドロ, Doro-hedoro) (2020) (screenwriter).Seraph of the End ( 終わりのセラフ, Owari no Serafu) (2015) (screenwriter).Terror in Resonance ( 残響のテロル, Zankyō no Teroru) (2014) (episode screenwriter).Attack on Titan ( 進撃の巨人, Shingeki no Kyojin) (2013–present) (episode screenwriter (season 1–3) screenwriter (season 4)).Panty & Stocking with Garterbelt ( パンティ&ストッキングwithガーターベルト, Panti ando Sutokkingu wizu Gātāberuto) (2010) (episode screenwriter).At the Crunchyroll Anime Awards, the former won anime of the year, while the latter was nominated for anime of the year and best fantasy.

In 2020, he did the screenwriting for Jujutsu Kaisen and Dorohedoro. Vinland Saga also won the award for best drama. In 2019, he did the screenwriting for the anime adaptation of Vinland Saga and the second season of Mob Psycho 100, both of which were nominated for anime of the year at the Crunchyroll Anime Awards. In 2016, Seko did the screenwriting for the anime adaptation of Mob Psycho 100, which was nominated for anime of the year and won the award for best action series at the first Crunchyroll Anime Awards. Seko also wrote the Attack on Titan: Lost Girls novel.

After doing episode scripts for Panty & Stocking with Garterbelt, Attack on Titan, and Terror in Resonance, Seko was put in charge of doing all the screenwriting in the anime adaptation of Seraph of the End.
