^ Oliver’s half sister (not that you don’t know, but others may not. :p) Avigail.
Oliver and Avigail have fought four times or so (unfortunately not in game because I don’t multibox. :<), with Avigail absolutely crushing him every single time. Though there are plenty more powerful and skilled than her, there is not a single person Oliver fears more in a fight.
Thankfully, she has long since become an ally.