What source? Rol be a cheater!
Anyway, in Ansem's Report 6 in KHII, his apprentices are listed as the first 6 Members of Organization XIII before they were Nobodies.
Kimi wa ne tashika ni ano toki watashi no soba ni ita
Itsudatte itsudatte itsudatte
Sugu yoko de waratteita
Nakushitemo torimodosu kimi wo
I will never leave you