Kotoko and Kuro discover where Rikka, his cousin with the same powers, has been living since their last encounter. They go to investigate the apartment, which has a grisly history.
The reason he didn't leave a note was either 
because he wasn't mentally able to...
...سبب عدم تركه لملاحظة كان إمّا لأنّه لم يستطع ذلك ذهنيًّا
Er hat keinen Abschiedsbrief hinterlassen,
weil er dazu gar nicht imstande war.
O motivo de ele não ter deixado um bilhete
foi porque ele não estava mentalmente capaz