Fed up with the Second Hokage's suspicions against the Uchiha clan, he plotted to take back the supremacy held by the Senju clan.
He had spiky, dark hair and dark eyes. He wore the typical Uchiha outfit consisting of a black, high-collared shirt and a pair of pants. He also wore a face guard that only covered his forehead and the right side of his face and a sash over his shoulder which held his rather large sword strapped to his back.
Being part of the Konoha Military Police Force, he was a fairly skilled shinobi and was probably skilled in kenjutsu due to the sword he wielded. He also managed to awaken his clan's kekkei genkai, the Sharingan, which granted him many benefits like the ability to see the chakra flow or copying techniques he witnessed.
Setsuna can mean "moment" or "instant" (刹那), or "painful", "trying" or "oppressive" (as a shorter version of 切ない, setsunai).