Reputation skills.

Nastya - "guilt," so I chose tears.
Anton - "anger," so I chose blood.
Sandor - "justice," tears and switching to blood.
Irina - "resentment," so I chose blood.
Kirill - "revenge," blood and switching to tears.

Is this, as I understand, the plan?
In campaigns, unlike battles, you can't change the path.

And I wasn't basing my choice on how cool the skills gained are, but on how cool the skills being enhanced are. And as a result: Tears are always preferable.
Because the mage has the strongest spells - summoning elementals (tears).
And warriors really like the "Predator" skill, which lasts 3 rounds with tears, instead of 1 as usual. But the best blood-based skills, like "Hero Strike with Squad" and "Extra Turn after Kill," aren't significantly enhanced by blood...