The Synthoid is my least favorite of the Kharn action figures, as least in the original paint scheme, which probably explains why it took so long for me to base one up!
According to the Final Faction background, the Synthoids are a type of autonomous mech. In fact, Earth mechs use tech derived from captured Synthoids. The chief weapon is the purple turbine-looking thing, which (in the video) whirls and shoots some kind of powerful energy weapon.
The rear view (above) show three screws holding the figure together, plus two accessories holes for adding supplemental weapons (available separately). You could improve the appearance by filling in the obvious holes, especially if you don't plan on using the accessories.
The arms and legs can be pulled off. The fit on the arms is poor, and can cause a visible seam in the body depending on how the arms are posed.
The only improvements I made to this toy were to touch up some of the red 'lights' where the paint was crooked, though perhaps I should have painted the entire bumps; I also used a silver marker on the armored parts. I then based the figure, and sealed everything with matte clear spray.
The basic right arm is known as the Maul Arm, and is a close-combat weapon. (It can be replaced with different arms from other packs.)
The left arm is known as the Claw Arm, and can be used in close combat to grab or attack an enemy. The hand will also hold many of the available Kharn hand weapons (from other packs).
I've only added one of these for my Kharn faction, as it's a powerful troop. I may eventually field some Synthoids with different weapon load-outs.