I was playing Fire Emblem If (暗夜) yesterday and came across a construction I did not know beforehand, な-adjectives apparently turned into adverbs using く.
お前{まえ}のことは、父上{ちちうえ}に上手{じょうず}く言っておこう
I am not sure I understand the function of 上手く
here. My rough translation is:
Let's prepare your father by telling him about what you did well.
But I am not sure at all about how 上手 fits into this sentence.