BioEditThe 212th Legion "Slayer's Fist" is/was the Separatist Empire led by Darth Slayer (Obi-Wan Kenobi) and Darth Sidious.
(The army is the fanon version of the 501st Legion or the Galactic Empire.)
The Separatist Empire was first formed during Order 88, when Jedi General Obi-Wan Kenobi became seduced to the Dark Side of the force by Darth Sidious after killing Jedi Master Even Piell on Coruscant while avenging Sidious.
The Legion was formed and renamed after what was left of the original 212th Attack Battalion led by Darth Slayer when he was Obi-Wan Kenobi during the Clone Wars.The 212th Legion eventually surrendered to the Rebellion Corps. (the Rebel Alliance) shortly after the deaths of Sidious and Slayer on the Second Nebula (Second Deathstar).
Commander Maw (Veteran Clone Officer)
Commander Hue (Veteran Clone Officer)
Lieutenant Boil (Elite Clone Officer)
Captain Appo (Senior Clone Officer; disavowed)