If you play Umber, and have an army of 5 trained units with 3 units in each group, each of those groups gets +2 (times 3, because there is 3 units in the group) attack as long as the 5 groups stay together.

Same with Tarth, but Tarth only works if you have 3 or less units in a group (the army).

Sincerely
~ Kongdej

Stop giving simple answers!

~ K

Champions and sovereigns count for these bonuses. If you have an army of more than 3 units the Tarth bonuses do not apply.

The Urxen bonuses are if you have 5 or more in your army you get the bonuses (although I haven't confirmed this yet).

The bonuses that they give you apply for each member of the group with that blood trait.

Example with a group of firebands (3 units in the group) they have a total attack of 27 when with an army of 4 or more. But with an army of 3 or less they have an attack of 36. (Tarth)

Basically the firebands have an attack of 9 and 3 units in the group and so the attack is 27.

Throw the bonuses in you get an attack of 12 and 3 units and so the attack is 36.