[Rune Son of Bjarne]

very simple because Morgoth alone of the valar knew fear! He might have been mighty but Fingolfin alone wounded him, he would not have been able to take Doriath unharmed.

about Rainor's quote: Well, it does not say that the silmaril transfers the power to the holder. . .as I see it Carcharoth was an instrument used for bringing the silmaril to Doriath (and some other stuff). The reason Carcharoth can enter is not that he has become more powerful than Melian, but because the Faith of the Silmaril is greater than her enchantment.