This honestly looks like you found/made a couple of pixelart bases and just went with that.
Many of these characters have different proportions and sizes that make them incompatible with that sort of method.
For example, khal drogo is a MOUNTAIN of a man and Joffrey is a tiny lil 13 year old. These bases put them at the same size when, in actuality, Drogo should be TOWERING over most of the cast here.
Go back over things and try to play around with everyone's proportions more, take free reign to exaggerate! Make drogo a big hulkman, make Jon Snow more of a willowy prettyboy, play around with people's features to make them more recognizably them!