Troius is a giant alien monster under the command of Warp Monarch and a supporting antagonist in episodes 47 and 48 of Chouseishin Gransazer.
After the JSDF and the Gransazers refused to hand over Ran, Brighton summoned Troius to attack Tokyo in order to force them into complying. In response, the Wind Tribe and Water Tribe summoned the Chouseishin Dorcruz and Leviathan to battle the beast with the help of the other GranVehicles and Youhi.
Despite the efforts of the Gransazers, Troius manages to fend all of them off, heavily damaging Dolcross and destroying Youhi. Garuda also intervenes in the battle but Troius damages it as well. However, it was then Guntras and Cloud Dragon enter the fight. After Guntras beat back Troius, Cloud Dragon blasted Troius and destroyed him.
Here you will find more information about it on the website
https://villains.fandom.com/wiki/Troius
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