All Rasyats come with Natural Born Warrior, a DA close combat weapon and CC 21. Combined with their Eclipse Smoke Grenades they can get into melee and mix it up with some of the best martial artists.
They are also competent ranged fighters. Between the 4 different profiles they have access to Combi Rifle, Combi Rifle + E/mitter, Boarding Shotgun and Grenades, or Spitfire for additional SWC cost. These packages let you tailor your Rasyat to the kind of enemy that you want him to engage and care should be taken to see what your list is lacking.
All Rasyat profiles have Eclipse smoke and PH 13 making them very effective at delivering smoke far up field and using it to cover their advance into melee. Rasyats are also ideal for getting smoke into the midfield at a minimum of orders and allowing other models to advance safely. Beyond this they have Armor 2 and PH 13. With Eclipse smoke they will often want to Smoke Special Dodge rather than shoot back.
Use Controlled Jump to get the Rasyat dropped right where you need them. It is also fine to have them walk onto the board edge to avoid taking enemy fire.
Remember that you can Speculative Fire an Eclipse Grenade, even from inside another Eclipse area. If fired within 8" you will be at target number of 10, which is not bad.
The Rasyat are Morats and will ignore Retreat and Loss of Lieutenant.
The biggest counterplay to a Rasyat is during deployment. Try not to leave large holes in your DZ where an enemy could drop in. It is also good to have models watching the long edges of the board where AD trooper like to walk on. The Rasyat is expensive so if an enemy army, especially a Morat Agression Force has large holes in it, expect a Rasyat.
The Rasyat will die to most kinds of ranged weapons and particularly hates mines or direct templates because they ignore his smoke dodge. Keep in mind though that if the Rasyat does Smoke Special dodge, you will not have to find a way to clear them out. This can be done by putting a trooper in Suppression Fire overlooking the Rasyat from a safe position, by dropping mines on them, or by Speculative Fire and Intuitive Attack. Whatever you do, be careful not to get too close. The Rasyat is more than happy to declare engage and come rolling out of the smoke to kill his would be assassin.
Rasyat are a good choice for AD in most combined army lists, but their use is especially good in scenarios such as Supremacy, Show Of Force, or Biotechvore where you need to move models up board in a hurry. AD troopers with Melee stats are also rare, so he is a good addition to a Melee weak force. Missions that require destroying objectives in the enemy half zone, such as Looting and Sabotage will benefit from a Rasyat who can place D-charges or simply beat on the objective with his DA CCW and Natural Born Warrior.
Most games the Rasyat will not be deployed because of AD: Combat Jump. However, you can always place the Rasyat on board if you know that you will have difficulty moving up board and want smoke in your own deployment zone.
Active Turn Role
Rasyats want to exploit holes in enemy forces, kill enemy lieutenants, or place smoke on enemy ARO pieces to disrupt their fire. They want to face their foes one at a time, and can hit surprisingly hard in melee. While most other CA Drop units want to destroy enemy troopers as fast as possible, the Rasyat should be used surgically.
Almost always the best choice in ARO is to drop Eclipse smoke and Smoke Special Dodge. The target number will be 16 and it will prevent further enemy fire without a large expenditure of orders. There are times though that shooting is better, such as when you can get multiple enemy models under the same template with a shotgun, or hit a Tag or HI with an E/mitter shot. Take such options when they are worth it but know it often means losing the Rasyat. Finally, once inside smoke the Rasyat should Engage against any enemy that passes within two inches.