This series is about battle spirits yet again, but this time, the spirits don't originate from Grand Rolo; it's not connected to Dan/Brave. The show is very plot focused, and has a lot of characters (the quote unquote 12 sword eyes, plus quite a few others).
Story: 9. This is a two parter show, that got separated for... no real reason, I assume. I'd give the story of this part a 9; it establishes the world well, the plot, the conflict, the events.. Since I'm not going to write a review for the second part, let me say that it doesn't worsen, but since it focuses more on the conclusion of the story, there aren't many more interesting ideas or locations that are brought (8/10).
Art: Good, 7/10.
Sound: No clue. The OP isn't bad, I don't remember the ED, the ending of the show has no music (copyright), and I forgot about the normal soudtrack, so I assume it's okay.
Character: I'd give an 8. There are too many characters for all of them to develop, but the show tries, and to me, succeeds. The MC, Yaiba (altough he doesn't develop as a character, he develops to the viewer), the purple sword eyes, the yellow sword eyes of darkness, the white and green sword eyes of light.. Most of those I listed are characters that I think are well executed.
Enjoyment: There's one thing that really annoyed me from the show, and brings my enjoyment to a 9, and my total score to an 8 (as opposed to a 10 and 9 respectably). That's the stakes. In a card game anime, you need stakes for each card game, or else it all feels pointless. Here, (slight spoilers for one of the first 10 episodes), they sometimes establish the stake, but, for good reasons, make the protagonists lose. However, due to the stakes being too high, they just back out of it. The way it's executed isn't bad, but it's something that I really don't respect. This happens more than once.
All in all, I'd give it a solid 8. I'd recommend to anyone who would like adventure and an intriguing story, and who likes card games.
FYI, the card game aspect is explained at the beggining of the show, and you should be able to get the hang of it. In fact, it introduces the game better than it's predecessors (Toppa, Dan, Brave and Heroes).
