It may seem like there is a lot of questing to do, to get the 22 bloods needed.
I wish to highlight something.
As you work on getting the bloods for this achievement, you are also making major in-roads into other achievements as well, that also give items!
i.e. Belt, Range, Cloak, Arms and Helm!
Plus once all done, will yield primary weapon and a shield item too from Tactician of Bloody Kithicor achievement.
Thats a total of 7 gear slots, + an augment.
(All of which are for level 75 required, 80 recommended)
To break that down a bit.
In Medicine, there are 5 rescue bloods to collect.
That is also the same activity for this Refugee Rescue achievement. Which rewards a belt. melee caster
As finish the 3 remaining bloods for Medicine, you are also 60% of this From East to West Commonlands achievemnt. Which rewards a range slot item. (2 quests not part of the blood series needed to complete) melee caster
3 bloods for Oblivion, and 2 blood for Light make up this Efforts of a Mercenary achievement which rewards a cloak. melee caster
The final 4 bloods for Oblivion have their quests in this The Army of Obliteration achievement which rewards an arms item. (1 quest not part of the blood series needed to complete) plate chain leather silk
The remaining bloods are also tied up in this The Army of Light achievement which rewards a helm. (2 quests not part of the blood series needed to complete) plate chain leather silk
I hope this helps in giving a better feeling of "rewards" versus "efforts" when looking at the achievement.