Fullmetal Alchemist: The Sacred Star of Milos

Both are good additions to the series they belong to and emphasis on fights/battles and you can't go wrong with that 

In both shows there's a lot of action and (as in one the protagonists use magic and in the other alchemy) a lot of special effects. Also, you'll enjoy these anime more if you're already a fan of the series (TOP videogame, FMA:Brotherhood series) 

Both are movie sequels based on extremely popular shounen series. Both have animation that can be described as laggy compared to the show but accurately depicts the main feelings and emotions of the original series. Both focus on some unique brand new, movie only characters that go through problems where the main protagonists use their ability to help them get through them. Both are better watched after you've seen a fine chunk of the series (Naruto to about 110 and FMA Brotherhood after about episode 16)