i jiust read the dutch version after reading the original one

and i think i know who RAB or RAZ (dutch) is

its

Spoiler Alert, click show to read: 
the brother of Sirius black
and his name starts with an R and ends with a B
he call him the Dark Lord what indincates to a deatheater
also he says he would be dead when this would be discobered
and R Black was murdered...maybe for destroying the horcruxes

ps the Z is Zwarts in dutch, thats why i thought of him, wich name would have a Z in dutch and B in english the only logic would be a member of the black family


more on this later