King Thorin's sister's name

[Dûrbelethwen]

I just finished reading Dante's inferno for my world literature class and I came across a name that could be considered disturbing considering the title I gave this thread. In the last canto the two main characters come across Satan, Judas, Brutus and Cassius. Another name that Dante gives Satan is Dis. I seem to remeber reading that Fili and Kili's mother's name was Dis. Does anyone have any thoughts on the matter.