[ Izanagi are ] into whatever makes money, and they protect themselves with an elite corps of Merc soldiers, fanatically loyal to the corporation, who call themselves "Ghost Warriors".
Dalton: Why do the Izanagi mercs call themselves Ghost Warriors?
Aida: It's the name of the fighting elite of the original Izanagi clan.
Well trained. Some live by the old Samurai code. Others are just in it for the action.
Izanagi Ghost Warriors are the strike force of the Izanagi Corporation. They directly appear only in Unreal II, however, there are multiple references to them throughout the whole Unreal series. Ghost Warriors are mercenaries and are hired by Izanagi and work for money.
There are three classes of Ghost Warriors: Heavy, armed with a Rocket Launcher and Flamethrower and has 500 Shield points; Medium, armed with a Shotgun and Magnum, having 300 Shield points; Light, armed with a Combat Assault Rifle and a Dispersion Pistol, having only 100 Shield points.
Ghost warriors first appear in Unreal II on Acheron, where they attempt to dig out an Artifact from a living planet. They were probably planning to sell the Artifact later on. On Severnaya, Ghost Warriors defend the Minkovsky Dam from an assault by NEG Marines. On Sulferon, Ghost Warriors defend the secret Izanagi research base and the valuable information there. On Janus, Ghost Warriors are attacking Axon's research facility in order to capture two Artifacts that are being held there. They use any methods that could help them reach the Artifacts, even torturing scientists. On Na Koja Abad, Ghost Warriors defend Izanagi scientists while they research new weapons and find a way to obtain another Artifact. However, they see little to no action there and seem to be bored.
In Unreal Tournament 2004, some of the Assault levels are remakes of real conflicts from the Corporation Wars. Izanagi Ghost Warriors made an appearance in AS-BP2-Jumpship, where they successfully captured a Liandri prototype jumpship and escaped back into Izanagi-ruled space. Strangely, in AS-Glacier, Izanagi Ghost Warriors never showed up, even though Lamdon 3 facility was an important one. Instead, the facility was defended by NEG Thundercrash force, maybe because they were elite warriors and Izanagi were in need of better protection.
In Unreal Tournament 3, the Ronin team is a part of Izanagi Ghost Warriors. They work directly for the Izanagi corporation, but the sole reason of joining the Izanagi strike force was to avenge the Necris (a side reason, though, was that the leader, Reaper, was injured and an Izanagi hospital was the closest). Ronin is probably a part of the Ghost Legion, wears red armor and has a Japanese-styled base.