Captain Rex "Bad Batch"

Character:
Strong-willed and independent, Rex could speak his mind even in the presence of high-ranking Jedi. At the same time, he unquestioningly carried out any order, as he believed that the mission should always be a priority.

Brutal, aggressive, and fearless, Rex is a master tactician and can maneuver around enemies with cunning in addition to his strength.

He has a good sense of humor, which Rex often used to defuse tense situations.

Has strong moral principles.

He became more dark after the Clone Wars.
Rex worked on rebel affairs, crossing paths with Squad 99 a couple of times.
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It's possible that Rex was looking for clones he believed hadn't yet been brainwashed and warning them about their implants so they wouldn't become pawns of the Empire. He could also be looking for specific clones, whether their chips were activated or not, to remove their implants and free them from Imperial control.

Combat skills:
An experienced hand-to-hand combatant, Rex was skilled in both armed and hand-to-hand combat.

A marksman, he was able to hit both fast moving targets and distant targets.

Jetpack Usage: Rex was skilled in the use of a jetpack, leading squads through the most difficult flight paths.

Military experience: He had a good understanding of intelligence and military tactics, and was able to lead specialized units of clone troopers in various operations.

A master tactician and leader, Rex was a skilled military commander and respected leader, earning the respect of his subordinates and peers.

A master of survival, he was skilled in mental resistance and was able to defend himself against a Force Mental Trick performed by the Dark One.
Acolyte Asajj Ventress.

Pilot: Rex was skilled with machinery and could pilot a Y-wing fighter with ease.