Morgana Prime is the main planet of SG. It holds all of the most powerful and most experienced players in the game. The level limit of units on Morgana Prime is level 60, and the SG Divisions levels max out at level 99. Heros that reach level 50 in a division can participate in Reincarnation events, and trade their experience levels, units, and most other things, to become more powerful on a permanent basis.
To visit Morgana Prime, enter the Star Portal (the swirling yellow rings around b4 of your Faction Capital, and click on the huge Matrix in the middle. Locate and select Morgana Prime, and click Go.