Halo Legends is a collection of anime episodes based on Halo. Each episode is done by a different team(except Origins and Origins II). The episodes don't really have an consistency between, all but 2 being stand alone stories. When it comes down to, if you are a fan of Halo, and you like anime, you probably already have this DVD or Blu Ray. Perhaps, however, there are some anime fans ot there that aren't really into Halo, but still want to know if they should. My answer is yes. The first 2 episodes, Origins and Origins 2 explain everything you need to know about the Halo backstory, so there should be little to no confusion.
One of the episodes is done by the same team that made Dragonball, and is non canon, but lighthearted and downright hilarious if you ask me. There's also an episode that details the rivaly between the Spartans and the O.D.S.T. and forces them to work together. Almost every single episode has something unique and itneresting, be it the oil painting art style of "The Duel", the comedy of "Odd Onne Out", or the emotion of "Homecoming", which details the grim truth about the spartan program.
I strongly urge every Halo fan to watch this, and even if you aren't, you still might want to give it a go.