Eileen's overall approach is one of "come on if you think you're hard enough" and try attacking her school of thought. She has no hesitation or compuction in blasting away any direct threat and always alerted the Queen to possible dangers coming up, something Hanastrew has taken over doing.
Eileen keeps herself fit, practices her wand firing and spell generation charms and seeks (and usually gets) pointers from the Queen. Eileen questions practically everything, annoying the Queen, though Eileen points out this questioning enables her to put herself in someone else's shoes and to deduce where threats come from efficiently.