Mercenaries and slots

Yes, you can sell mercenary that you don't use anymore. 

Yes, if you sell the mercenary, you will not need to buy slot again.

The final price of a mercenary is influenced by the upgrades.

If you sell a mercenary with upgrades, they will remain in case of its further purchase. 

Maximum amount of slots in sets is 12. It means that maximum amount of mercenary that the player can have is twelve. 

Unfortunately, it's impossible to buy a mercenary if you don't have free slots.  

Yes, you will need a free slot as well as for non-premium mercenary.

Remember, when you buy a mercenary you firstly need to research it with experience points. And only after that you can buy it with silver. 

If you stay the last person from the team you can't choose any other mercenaries from the set. 

Premium mercenaries have following advantages:

- Better earn silver and experience points
- Improved consumables