She's pretty much beaming whenever she's doing something she loves, like looking at weapons, fighting, adventuring, or talking about Rudeus. It's jolly good how strongly and consistently her personality has been depicted throughout the series. Back when she was just a waste, she was still the same but not focused on anything constructive, so she behaved like the worst spoiled noble brat. Under Rudeus's tutelage and the realities of the unexpected, long adventure, all of her energy became her genuine strength instead.

A fine extra episode. The excellent fighting scene left nothing to be desired. It was a rather interesting change of perspective to have a n00b follow Eris, to present her as an expert in that sense. She's far too easily provoked, but otherwise she almost behaved like a pro.