ERMAC
Unlock and play as different and cool variations of Ermac, and here's how you can do this:
Normal Ermac is available at the beginning of the game. Available in Mystic, Spectral and Master of Shoals. All of which have different advantages and disadvantages playing as.
Tournament Ermac - To play as tournament Ermac you have to either unlock him in the Krypyt or do what I did and that's win a klassic tower as Ermac at any level of difficulty.
Pharaoh Ermac - In my opinion my favourite version of Ermac, I often play as this version in Mystic. This version is available in a Horror Pack which includes this Ermac, a Vampiress Mileena and a Kraken Reptile, which you can purchase for £3.75.
Klassic Ermac - as far as I know, I got this version free with Tournament Ermac when I completed the tower battle. I don't know any specific detail as to how you can unlock this version, but it's free.
Krimson Ermac - this variation you can buy for £2.37.
That's all the variations of Ermac covered, I hope that this was useful to you.