Rebootomnitrixsymbol This article belongs to the Reboot Continuity

Grey Arms is a fusion of Four Arms' DNA and Grey Matter's DNA. He cannot be accessed unless the Omnitrix is tampered with.


Grey Arms has the body of Four Arms, but the head of Grey Matter (although much larger). He has three eyes, two of which are those of Four Arms and one is a large Grey Matter's eye. He has one arm of Four Arms on his right side and 3 arms of Grey Matter on his left side. His right leg is Grey Matter's and left is Four Arms'.

Grey Arms wears the Omnitrix symbol on his chest.

Powers and Abilities

Grey Arms, being half Tetramand/half Galvan, has enhanced strength, albeit he's not as strong as a Tetramand due to the asymmetric body of the fusion and not being pure. He also has shown higher intelligence, probably coming from his Galvan part.


Due to his asymmetric body and having one functionally strong arm, he can't use his enhanced strength. In addition, he suffers from imbalance issues.


Ben 10


Ben 10

Season 1

Naming and Translations

Language Name Origin
Italian Materia Grigiax2 Translation of English name


His name is the combination of Grey Matter and Four Arms.


  • Grey Arms is the first fusion alien in the reboot continuity.
Original Aliens
CannonboltDiamondheadFour ArmsGrey MatterHeatblastOverflowStinkflyUpgradeWildvineXLR8
Introduced in Season 1 Introduced in Season 2 Introduced in Season 3 Introduced in Season 4
Gax RathShock Rock HumungousaurSlapback Jetray
Omni-Enhanced Aliens
CannonboltDiamondheadFour ArmsGrey MatterHeatblastOverflowStinkflyWildvineXLR8
Omni-Kix Aliens
CannonboltDiamondheadFour ArmsHeatblastHumungousaurJetrayRathShock RockSlapbackXLR8
Fusion Aliens Not In The Show Non-Canon
Amalgam BenGrey ArmsXLRArmBlastDiamondHeat Mole-Stache Banana AlienHot Dog AlienOmnitrix Glitch FusionRath ArmsShock Blast
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