The Omnium Beast Right Arm is one of the parts you need to collect to obtain the vehicle called the Omnium Beast. You need to unlock Banges and find giant aberrants called Behemoths, which drop the Omnium Beast Right Arm at an extremely low chance (approximately 0.25 to 0.50 percent). The drop rate is even lower than the chances of getting an SSR in the gacha, so you'll need a lot of luck to score this vehicle part.
All Behemoth locations in Tower of Fantasy
Reference the images below for the location of all Behemoths in Banges. These mobs respawn after a few minutes, so you can repeatedly rotate between the three areas to farm the Omnium Beast Right Arm.
Head to the area circled in the image above in HT201 Shelter to find a Behemoth named Surtur. Defeating it for the first time will grant you an Achievement of the same name.
Head to the area circled in the image above, north of Banges Farms, to find a Behemoth named Bergelmir. Defeating it for the first time will grant you an Achievement of the same name.
Head to the area circled in the image above by the Seventh Day Forest to find a Behemoth named Mimir. Defeating it for the first time will grant you an Achievement of the same name.
How to defeat Behemoths in Tower of Fantasy
Behemoths are formidable enemies that generate strong shields and deal powerful attacks. However, their size makes their attacks relatively easy to dodge. These mobs are notoriously weak against the Flame Element, so consider bringing a weapon of this type (preferably a shield breaker) to help you farm faster.
Check out our guide on How to get an Omnium Beast Left Arm in Tower of Fantasy to find another part of this vehicle.