Kakyou Kuzuki has the ability to see how the future will unfold itself in his dreams. In one dream, he meets a young woman named Sumeragi Hokuto and begins to see the tragic future yet to be decided by the Dragon of Earth and the Dragon of Heaven.
summary by Eek
Highs: Good preview for the television series; different ending theme song
Lows: Not much more than a lengthy, spoiler-filled trailer
It would be fair to refer to X: An Omen as “Episode 0” seeing as how it is a prequel of sorts for X. While it is good in a technical sense and asks many questions, there really is no point in watching this if you have seen the television series.
An Omen starts by introducing Kakyou Kuzuki, one of the dream seers in the television series, and then it sets out to do what any other trailer does: establish the stage and present major characters for what is being previewed. His presence here cements him in the series by featuring part of his background that is never revealed in X. While much of the focus of this OVA still remains on Kuzuki, all of the other main characters are given some screen time to illustrate the gravity of their individual and overall situations. In addition, a bonus comes at the end in the form of a new end theme song that was specifically made for this OVA. Sung by Koizumi Kouhei, Strength is a good J-Pop treat, even if it is not anything out of the ordinary.
However, there are inherent problems with a trailer like An Omen. If you have never seen X, you are going to be showered with spoiler after spoiler. Being the length of a regular episode, most of the content is taken from the series, and many unforeseeable parts are blatantly given away. On the other hand, if you have seen the television series, this is a waste of time. Sure, Kuzuki is fleshed out, but you already know the outcome of many revelations and characters, even if this can serve to remind you of certain events.
X: An Omen is merely foreplay for a good anime. Watching it may cause fans of the series to drool like a Pavlovian dog, but if you have never seen X, it will spoil many parts and may ultimately deter you from experiencing the television series to its fullest.