Hi,
unfortunately the only info i was able to find about it is in Russian, so the quest names are probably not accurate, hopefully you should still be able to figure out which is which if you talk to the NPCs, if not then just let me know in game. :)
Blood for Blood [20] (Explorer Pelanir) requires you have completed two other quests: Long roads in the dunes [19] (Pelanir), and Salvation on/at arrow head [19] (Pelanir). This second quest is a part of a quest chain, it should be available after completing the following quests: Breath of Filth [19] (Pelanir), Lost in the sands [19] (Pelanir) and Chaos Poison [19] (Elder Verkiry).