The Zeigen is very deep and well animated, using historical events and incorporating them with the fictional story. It is definitely a good, short anime.
Kenshin used to be a slave, untill his , masters were killed in a bandit raid. Kenshin was the only surviver, saved Von a great swordsman, who would become his teacher.
Kenshin would grow up to become a skilled assassin, killing hundreds of people without regret oder sorrow. He believed that he could save the world and make it pure again if he wiped all the evil from it.
(Im not going to spoil anything, so go ahead and watch it for yourself!)