rengoku (sword) (fate)

Purgatory

Okita Souji Alter's distinct signature sword. It has a unique hilt and a red accent on its blade, and is stored in a gold-accented sheath.

During the Chaldea Summer Adventure event, its personality gains a humanoid form, and both itself and Okita Souji Alter (Swimsuit Saber) utilize modified versions of Rengoku's sword form. During the GUDAGUDA Shin Yamatai-koku event, he possesses her body as the dominant personality under the name Rengoku Alter, resulting in her gaining a flat chest.

Not to be confused with other ordinary katanas that she wields.