Board Thread:Shadow Fight 2 Discussion/@comment-26009886-20160329070005/@comment-26958678-20160329073114

If you have at least one Volcano key it will be restored to 5. Others are same.

My advice is use all but 1 Volcano key to get Megalith keys. If you finish Volcano with the most damage you will get two megalith keys, or a charge and a key. After you collect Megalith keys 5-8 is possible, go to Megalith and collect Fungus keys.

After season ends you will get some charges. And +4 Volcano key. You can use your keys to get more megalith then more fungus then vortex. As long as you have that one Volcano key, you can always make other keys. Keeping charges and Using them against Vortex is most logical way. He has 22,000 shield with 16 minutes which makes him harder than other bosses.