Adds a fair bit of content, the culture is very flexible unlike the previous one that was released.

Each primal animal has a different stacking buff, after 5 stacks you gain a new effect to your attacks, and depending on the unit, you may have an ability to spend the stacks of the effect.

Base Units for the Culture:
T1 Dart Unit, a Ranged Unit that shoots darts, has unique animations, unfortunately as a T1 probably won't see that much use, does have a disengage mechanic
T1 Shield Unit, has a built-in Heal
T2 Shock Unit, looks somewhat like a Berserker, the unique mechanic it has is to do an AoE Cleave Charge
T2 Support Unit, mostly standard fare healing, once the stacking mechanic has triggered the passive effect, you can summon a T2 Mythic Unit of your Primal Animal, which is very strong
T3 Polearm Unit, leaps into the enemy and goes into defense stance

Tomes
T2 Fey Mist
Gives a good T3 Skirmisher with the leap back mechanic, reasonably strong
New Staff enchant for supports, provides a buff for the unit
Clinging Mists makes your units harder to hit, stacks
Minor racial transformation that makes your units unaffected by the miss chance of the clinging mists, gives them random buffs when in the foliage

T4 Stormborne
Empowers coastal cities a lot
New Naga Transformation
Stormbringer is a T4 Racial Skirmisher, reasonably powerful

There are some other additions, but honestly the free patch is where a ton of content is added. Necromancy has seen a huge revamp.

Adds a fair bit of content, the culture is very flexible unlike the previous one that was released. Each primal animal has a different stacking buff, after 5 stacks you gain a new effect to your attacks, and depending on the unit, you may have an ability to spend the stacks of the effect. Base Units for the Culture: T1 Dart Unit, a Ranged Unit that shoots darts, has unique animations, unfortunately as a T1 probably won't see that much use, does have a disengage mechanic T1 Shield Unit, has a built-in Heal T2 Shock Unit, looks somewhat like a Berserker, the unique mechanic it has is to do an AoE Cleave Charge T2 Support Unit, mostly standard fare healing, once the stacking mechanic has triggered the passive effect, you can summon a T2 Mythic Unit of your Primal Animal, which is very strong T3 Polearm Unit, leaps into the enemy and goes into defense stance Tomes T2 Fey Mist Gives a good T3 Skirmisher with the leap back mechanic, reasonably strong New Staff enchant for supports, provides a buff for the unit Clinging Mists makes your units harder to hit, stacks Minor racial transformation that makes your units unaffected by the miss chance of the clinging mists, gives them random buffs when in the foliage T4 Stormborne Empowers coastal cities a lot New Naga Transformation Stormbringer is a T4 Racial Skirmisher, reasonably powerful There are some other additions, but honestly the free patch is where a ton of content is added. Necromancy has seen a huge revamp.