When Kill Bill met Old Boy they had a child. That child was named Akane. Backstory is minimal but I'd guess that Akane is a bodyguard or assasin.
Her last mission/job has gone wrong. Trapped in a town square; she knows she's dying tonight but is gonna take as many baddies with her as she can!
I'm digging this game so far and it cost 89 pence on the UK store during a sale. Normally its 4 or 5 quid but its worth it at that. Careful if you play it after you get home from work - its great for five mins but also three hours straight!