Imagine if all of the Great Sith Lords lived in one time period, paired up, and wielded great armies of troops under their command. Here is how I paired them up:

1. Darth Sidious, Darth Plagueis & Asajj Ventress With The Imperial Forces
2. Darth Tyrannus, Darth Maul, & General Grievous with Droid Army(Super Battle Droids, Hailfire Droids, Spider Droids, and Magnaguards)
3. Darth Vader, Darth Venom(Luke), & Darth Caedus(Jacen Solo) with the Episode III Clone Forces
4. Darth Revan, Darth Malak, & Darth Bandon with the Sith Troopers
5. Exar Kun, Darth Bane, & Xanatos with The Episode I Droid Army
6. Darth Nihilus, Darth Sion, & Lumiya with an army of Mercenaries, Bounty Hunters, Geonosians, Gammorrean, Killiks, Kaleesh, Trandoshans, and Sanyassan Soldiers.

Here are the Battles
1. Revan, Malak & Bandon's Forces vs Nihilus, Sion, & Lumiya's Forces
2. Exar Kun, Bane, & Xanatos' Forces vs Sidious, Plagueis, & Ventress' Forces
3. Tyrannus, Maul, and Grievous' Forces vs Vader, Venom, and Caedus' Forces