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.

In the campaign, I developed reputation based on my understanding of the morality of the factions:
Necropolis - blood, Haven - tears, Sanctuary - tears, Inferno - blood. For the Stronghold, I also wanted to choose tears, but in the second mission, the quest for blood gave me the orcish staff I needed, so I went with blood.

In general, for each class of each faction, one path is usually obvious. Moreover, most often, it's blood. Or rather, it seemed to me that warriors have a better blood skill, and mages have a better tears skill. Although this is more of a personal preference depending on the tactics.