These characters can be obtained by doing challenges.
In order to enter the secret area you have to get a key in the townhall playing events. These events can be played once a month, give you rainbow stars and one of the 3 chests has the key.
The secret area is located in front of the gnome room in the sewers.
Here there will be four challenges that can be opened with keys. These keys can also be obtained by playing events in the townhall.
The portals of the challenges are of different colors and can be opened with the key of your color. If you have the red key you will be able to open the red portal.
You can get one key per event.
When you complete a challenge you will get a code that you have to write down or take a screenshot to use at the end.
This is the Code
Battle with Gnomes
After that you must go to the portal in the center of the secret area and put the code to fight the gnomes.
The Portal in the Center
To put the code you must activate the lever and stand on the symbols in order.
Do this with the four challenges!
When you kill the gnome king you must go to the final part of the secret zone, enter the portal of the challenge you completed and take screenshots of the symbols.
When you have done all the challenges you must enter the portal in the center of the secret zone and enter the code.
What is the Code?
The symbols that you have to enter are those that were not in the portals.
When you do all the challenges this portal will open containing the chests of the characters.