Nimi-san has gone against the Shinsengumi. To avoid anymore problems they want to get rid of Serizawa.
An illness made her 
grow unable to remember
أصيبَت بمرض جعلها عاجزة عن تذكُّر
Una malattia l'aveva resa incapace 
di ricordare chi fosse o riconoscere chiunque.
Sua doença a impedia de lembrar quem era,
 e de reconhecer outras pessoas.
Болезнь заставила её забыть себя
и всех вокруг, включая меня.