Law conveying the will of Rosinante through his blade
After the moving flashback we just had it feels good seeing Law take all the emotions he has for Rosinante and channel it through the purpose he inherited from him i.e. to stop Doflamingo. Doflamingo may ultimately be Luffy’s opponent, but having the focus centered around Law and Doflamingo for the moment does serve the purpose of increasing the weight the fateful day thirteen years ago had, for both Law and Doflamingo. Law is using memories of that day to focus his wrath while Doflamingo is becoming unsettled by the day he would like to forget.
12Dimension 