Ebony has a lot of different emotions, that she uses.
Here are 6 of her most common ones. ^^

regular: most common expression, generally positive face
sad: only shows up, whenever Ebony is severely depressed
angry: hurt anyone who's close to her and you'll face this emotion
mischievious: Ebony used nasty plot, you better run
jealous: tsundere-mode activated. the question is: why?
happy: not all too common, but sometimes she's just really happy