This is a special time-limited Event, throughout which you will receive Blood Stones for each purchase you make.
What are Blood Stones?
Blood Stones are special points that you receive for each purchase during the Event.
Where can I find my Blood Stones?
There is no bar that indicates your total number of Blood Stones. However, you can Track the Blood Stones you need till you can collect your next reward at your in-game Bank.
What is a Trunk of Power?
Once you have collected the required number of Blood Stones, you shall receive a fantastic prize – a Trunk of Power.
There are several different types of Trunks you may receive; each contains different Bonus Items. Once you have earned a Trunk, it is automatically moved to the Black Market -> Items -> the 'Misc' tab
How can I find and open my Trunk of Power?
Once you earn a Trunk, you may open it to start using the Items within immediately or, if you prefer, later. Your Trunks are stored at the Black Market -> Items -> the 'Misc' tab.
Hence two possible ways to open the reward are:
- Immediately (via the "Congratulations!" pop-up window)
Once you click on the "Open Trunk" button, all Items within will be added to the appropriate tab at the Black Market -> Items tab . 
- Later (at the Black Market)
If you close the "Congratulations!" pop-up window, the Trunk you earned will be stored at the Black Market -> Items. You may find it under the “Misc” tab. 
Can my Blood Stones be vanished?
Yes, all Blood Stones you have accumulated will vanish when the Event is over.