Everyone's favorite ex-wife of Giles, Hannah may not be quite the resource and people person that Giles (well, the other Giles) is, but she's got some skills of her own. As a bounty hunter with years of experience taking down monsters and demons, she can hold her own in most fights, enough that you won't need to worry about protecting her as much as you might with, say, some other companions... And she makes a good pairing with other characters, especially those heavy in the smarts and weirdness but weak on the fighting.