Doriath, the doom weaver.

[Hot, crispy nice hobbit]

Actually, the "Doom" had always been there since the Music of the Ainur.

Then Illuvatar spoke, and he said: 'Mighty are the Ainur, and mightiest among them is Melkor; but that he may know, and all the Ainur, that I am Illuvatar, those thing that ye have sung, I will show them forth, that ye may see what ye have done...'

Mandos is the Valar of Doom, but he is not in charge of fate. Eru is. The Silmarils are said to lock the fates of Arda:

and Mandos foretold that the fates of Arda, earth, sea, and air, lay locked within them.

The fate of Beren and Doriath is linked with the Silmarils, because of Thingol's ploy to get Beren killed while stealing them from Morgoth. Maybe Doriath is sort of "jinxed" after the forced entry of Carcharoth?