Okay, with the Jedi Sentinel out of the way it’s time to lay out the groundwork for his evil twin classbrother, the Sith Marauder.

Sith Marauder Leveling Spec

Defensive Forms (1/2), (2/2)
Dual Wield Mastery (1/3) , (2/3), (3/3)
Enraged Charge (1/2), (2/2)
Narrowed Hatred (1/3),(2/3), (3/3)
Ataru Form (1/1)
Ataru Mastery (1/2), (2/2)
Execute (1/2), (2/2)
Enraged Assault (1/2), (2/2)
Blood Frenzy (1/1)
Towering Rage (1/2), (2/2)
Gore (1/1)
Rattling Voice (1/2), (2/2)
Erupting Fury (1/2), (2/2)
Sever (1/3), (2/3), (3/3)
Overwhelm (1/2), (2/2)
Massacre (1/1)
Malice (1/3), (2/3), (3/3)
Ravager (1/2), (2/2)
Brutality (1/2), (2/2)
Enraged Slash (1/3), (2/3),(3/3)
Form

Shii-Cho Form until you receive Ataru Form
Companion

Quinn (Heals) until you receive Lt. Pierce (Range Tank)
Rotation

Force Charge > Force Scream > Battering Assault > Smash > Ravage > Vicious Slash > Assault

At Level 30: Force Charge > Force Scream > Battering Assault > Gore > Ravage > Vicious Slash > Assault

At Level 40:   Force Charge > Force Scream > Battering Assault > Massacre > Gore > Ravage > Assault