Yu gi Oh! Zexal (pronounced "ZECK-sul" in the English dub, and "ZAY-al" in the Japanese version) was a 2011-2012 anime series based on the ongoing manga series, and forms the fourth entry in the Yu Gi Oh anime franchise.
Set many years after the events of 5Ds, the series makes a shift back to the more fun orientated days of GX, but still retains some serious overtones, although not half as grim as some sections of 5Ds were.
In this series, Duel Monsters is still a popular game, however by this time, the 3d holograms and duel discs of previous eras have been replaced by an augmented reality system, controlled and viewed via a system known as the "Duel Gazer", which superimposes creatures and battlefields over existing terrain.
Most of the series' action takes place in Heartland City, home to Yuma Tsukumo, a teenage boy who lives with his grandfather after his parents vanished in mysterious circumstances (this is one of many parallels between Yuma and Yugi Moto).
One of the recent crazes in the Duel monsters game is the introduction of XYZ (pronounced "ECK-seez") monsters, a new game mechanic which allows players to fuse their existing monsters to summon a special, and usually very powerful, creature from their extra deck, however, at the beginning of the series, Yuma has still to obtain any XYZ monster cards, never mind play them, which puts a bit of a damper on his ambition to become the worlds number one duellist.
During one duel though, Yuma finds that the pendant given to him years ago by his father contains a secret, it is actually a mystical key which allows him to travel into another plane of existence, which in turn frees a being named "Astral". Astral came to Earth many centuries before but was involved in an accident which erased his memory, and the only way he can regain his memories is by helping Yuma collect the "numbers", a series of 101 XYZ monster cards, each of which contain some of his memories. Matters are made more difficult due to the fact that only Yuma and a handful of other people can actually see Astral, so many people assume Yuma is crazy when he starts talking, and sometimes arguing, with himself during duels. However, Astral and Yuma find that they can combine their bodies and fight as one, which makes defeating some of their more powerful opponents much simpler, as Astrals duelling skill can combine with Yumas enthusiasm and resourcefulness.
Zexals original run of 73 episodes was followed up by Zexal II (Zexal second) which ran for another 73 episodes from 2012 to 2014.
Zexal II continued Yuma and Astrals adventures as they struggle to save Earth from invasion by a race of aliens called the Barian, who are enemies of Astrals people and agents of chaos.
Zexal isn't a bad series, its much more fun than 5Ds but still struggles to recapture the fun atmosphere of GX. The series introduces (and grossly exaggerates) the XYZ mechanic to the game, and as such most of the series' storylines revolve around the search for and use of XYZ related cards, at the expense of many much more popular cards that are/were being used in the real world game, but that is to be expected as the series was basically a long advertisement intended to sell game cards to the viewer.
I don't mind this series, but its certainly not the best one, with over the top characters and sometimes difficult to follow plots (probably something lost in translation), although I must say that the animation quality of the show is spectacular, with some of the duels being fairly exciting to watch.
I think that what they were trying to do with this series was essentially a reboot to the franchise, hence why there are so many similarities between Yuma and Yugi, but it just didn't seem to work terribly well.