Is the 'deg' a softly mutated 'teg', meaning the adjective "fair"/"just"/"impartial"/"unbiased"?
If so, then the two adjectives are not separated by the conjunction "and" (I mean 'a' in Welsh). Is this what causes the soft mutation of 'teg'? (I recall that adjectives that come before nouns cause soft mutations, such as 'hen'.)
Lastly, is this an emphatic sentence, since the verb is not first? If so, how come it doesn't take the form 'ydy'/'yw' instead of 'mae'?