You need to have a level 3 castle to unlock the Mage and I think you need to have 12 HL unlocked to get a level 3 castle.
You need the level 3 castle to unlock the Mage. Once you've unlocked it, it is at the upper right of the marketplace page just to the right of the alchemist.
and for future reference, there is a thread by Dillybar where u can ask all your kaw related questions. That way, there are less short threads like these in the active topics
You'll need to upgrade your CLAN CASTLE in order to get to the MAGE. If you have already upgraded your clan castle, just tap/click on Market then you will find what you are looking for. If you want to know/ask more about this game.. Please feel free to chat with me or you may use World Chat, i am sure there are alot of kind people that can help you out unlike forums trollers exist.
Unlock 12 highlands, upgrade castle to level 3 (costs 10b) and there you have it the Mage is unlocked. It can be found in the marketplace next to the alchemist.
A few things like the people above me said 1. Need 12 HL and lvl3 castle 2. On idevice it's under marketplace, on PC it's on the side bar, android not sure 3. Questions like this either belong in wc or dilly bars question thread. 4. This will be /eagled soon