From The TimeSplitters Wiki

TimeSplitter (#1) from TS1

TimeSplitter (#2) from TS1

Reaper Splitter from TS2

Scourge Splitter from TS2

Berserker Splitter from TS:FP

The TimeSplitters are a alien race with the ability to travel through time, space and dimension. They are the main enemies in the series and where created by Jacob Crow as "humankind's genetic superiors". There are 5 types of TimeSplitters in the whole series, this excludes the Drone Splitters because technically they are not TimeSplitters but an amphibious race that were enslaved and given TimeSplitter abilities.

During the events of TimeSplitters 2, a group of TimeSplitters took control of a Space Station, and kept the Time Crystals there. However, when Sergeant Cortez and Corporal Hart arrived on the Space Station to steal the Time Crystals, they started moving the crystals through time, so it would be harder for the humans to retrieve them.

Finally, during the events of TimeSplitters: Future Perfect, an army of Berserker Splitters led an attack on the rebel base, which was possibly an attempt to stop Cortez getting the Time Crystals back to there. The TimeSplitter mothership was shot down by Cortez, in an attempt to save his past self, and to stop any more advances of Berserker Splitters.

The TImesplitter army created by Crow was done so during the Machine Wars, which could have been a cover-up for this act.

Crow eventually turned himself into a splitter (Splitter Crow), to live forever.