Chigrik at Glade of Dreams and Gloum at Barrow of Sadness are waiting for heroes that want to increase their combat features. For just 30 they are willing to sell an unlimited quantity of Blue Sack to anyone that so desires.
In the bag you can find a random tablet, which will always improve your characteristics, or its fragments:
If you are not lucky enough to find the tablet straight away, do not worry. By collecting the necessary amount of fragments, you can exchange them for a random tablet. The table below shows the number of fragments and types of tablets.