Skill Description of Infantry Rush..

Her skill gives the effect of heavy blade to all infantry unit within 2 spaces, and this skill probably works on player phase like heavy blade. It's not very practical in use. x)

When Noire is within two spaces of an infantry ally, that ally will gain an extra special charge on every attack they perform (not attacks they receive) if their atk stat is higher than that of the unit they're fighting. So if your ally is up against +atk M.Grima or L.Hector...you better have 61 atk or nothing special will happen (if you'll pardon the pun)