[Morgeruat]

I would also tend to say she was a fighter, she doesn't exhibit any real thief abilities, and any she might have had would have been much more effective as a vampire than a mortal thief (need to hide in shadows, or move silently, turn into a bat or mist (same thing for getting around climbing walls), need money, charm someone and get it as a gift.

There is also no requirement for the leader of a thieves guild to even be a thief, merely someone with enough influence in the underworld to be respected (Artemis Entreri for example was an assassin and took control of a thieves guild, and while assassins are related they generally coexist with theives rather than working with or for them.

It can easily be assumed that she wasn't a cleric or she wouldn't have gone ahead with Jonny boy.

I would say ranger possibly, but she would have shed any ranger characteristics over the intervening years as her appetite demanded that she habitate near her food source, and she really never goes out into the woods where her training could make a difference.

So fighter makes the most sense, they tend to get into brawls which works well with her pension for melee (yes there are fighter archers, but the class tends to favor melee heavy warriors more)