"Warrior brotherhood" is an artifact costume in the StrikeForce Kitty series, based on a Brotherhood of Steel soldier from the Fallout video games, wearing the T-51b power armor and holding what appears to be a minigun.
StrikeForce Kitty 2
"Warrior brotherhood" adds 20 strength, 14 health, and 21 speed to that kitten, for a total of 42 strength, 33 health, and 35 speed, from "Depot boy".
StrikeForce Kitty: Last Stand
"Warrior brotherhood" is a costume that can be obtained from defeated raccoons in StrikeForce Kitty: Last Stand, look on pages in the "Ranged" category.