On occasion he may not sell the bow, but instead have it equipped. If this occurs then it is still possible to obtain it via pickpocketing and using the Misdirection perk. It is also possible to use the Misdirection perk to give weapons of greater value and stats to Falas Selvayn through pickpocketing. Once this step is completed, it will be necessary to steal back a couple of the weapons given to him until he unequips the bow, thus making it purchasable through his inventory.
The easiest method can be done without pickpocket perks and without Bend Will. Give him a dagger and attack him. Once he is hostile, keep attacking him until he gets on his knees. Once he is on his knees, open the map menu and fast travel at the same place (Ramshackle Trading Post). You can now buy the bow normally.
"Wielder receives an increasingly powerful blessing for every 20 animals killed by the bow. x animals killed"
Wielding the bow grants an ability called "Blessing of the Stag Prince." This blessing becomes increasingly powerful for every twenty animals killed by the bow.
Initially, the blessing grants an additional 5 points of Health and Stamina while the bow is equipped. This figure increases in increments of 5 for every 20 animals killed, up until 100 kills where the blessing maxes out at 25.
- The title of the bow and its enchantment are a reference to the Daedric Prince Hircine who is commonly depicted as a man wearing a stag's skull over his head, as well as the fact that it can be bought from a merchant in Solstheim, where Bloodmoon occurs, which featured Hircine prominently.