Rath was designed as an experimental version of Thar to test V2 gameplay rules.
Rath has 6 Socketed Outposts, 4 controlled by neutrals, and each team controlling one Outpost near their Fortress. A Lockbox spawner sits in the middle of the map. It first spawns at the 90 seconds mark and continues to spawn in 5 minutes intervals after that.
It is nearly identical to Thar but is lacking a middle. In addition, some changes (most notably, the widening of the island) which affected Thar did not affect Rath (because Thar is in the map pool while Rath is not).
See Thar for strategies.
Strategies on Rath are very similar to Thar. The major exception though is the lack of a middle. Because of this, the bottom island outpost is very important and pushing is a lot harder. Cheese is even stronger than on Thar because it allows you to establish a direct pathway to the enemy fortress in the absence of a middle outpost.