Evolving Buildings are a special new building type. These buildings give you several resources, like Population, Culture, Coins, Supplies and other resources. By evolving your building from Stage 1 to Stage 10, you can increase the values of the benefits given. Initially, only one auto-production is active, but more different resources can be added by evolving the building to higher stages.
Each Evolving Building has two different factors that affect their values and bonuses: Chapter and Evolution stage.
In order to evolve an Evolving Building, a special magical item (e.g. Phoenix Artifact for Phoenixes from Evolution of the Phoenix) is needed to trigger the evolution.
Once you obtained these special evolution items from the respective event, you can push your Evolving Building to the next stage in the Evolve tab of the building
With each new Evolution stage reached, the building becomes more powerful and new automatic productions are added to the list of resources and/or items produced once certain stages are reached. Some Evolving Buildings, like the Fire Phoenix, Storm Phoenix and Aureate Phoenix are alive and act as Pets. They provide for additional bonuses upon being fed.
Pet Buildings and Feeding
Some Evolving Buildings are alive and, given the proper care, will unlock additional bonus effects. All you need to do is make sure that you keep your pets well-fed and they will provide you with their bonus for as long as they are not hungry!
Bonuses can include lots of city-wide effects, such as increased Unit Damage, Bonuses on Magical Manufacturing Enchantment Effect or a boost on Goods production, among other things.
All you need to do to keep your Pets fed is to provide them with Pet Food.
Pet Food Instants can be crafted in the Magic Academy when an appropriate recipe is available. During special events in which Pets can be obtained, Pet Food can also be obtained as a reward for finishing certain quests in the quest line.