Omega is one of the three skins released under the monthly Dark Dimension Zone offer. It could be individually purchased with game coins in early May 2018.
Omega could be purchased in the Skins Shop under the ‘Dark Zone’ tab for 490 coins. This skin was available for a limited time and may not be available for purchase in the future.
Details of this skin may vary depending on location, platform or time.
Note: The Dark Dimension Zone offer with the Omega skin was released again for a limited time in late August 2019. The cost for Omega remained the same at 490 coins.