As it (finally) appeared as event as well, here are the first numbers - I know everyone knows it takes the exact number of energy crystals stated in but at least players who want to upgrade it can have an idea about the amount of them needed .
I could only go to lvl 4 so ... here it is:
lvl 1 - 62 stones
lvl 2 - 115 stones
lvl 3 - 178 stones
lvl 4 - 257 stones
lvl 5 - 348 stones
Other players who could go further and have the numbers for levels after lvl 5, please feel free to complete and come with adds .