Ten years after the evil lord Dhaos was sealed away, preventing him from invading Aselia, he has been set free by his loyal minions. His goal is to take control of the mana tree. With powerful sorcerers falling by the wayside, it seems that no one can stop Dhaos – that is, no one except a group of teenagers who must travel to the past to prevent Dhaos from being reborn! Now, Cless, Mint and Chester must find a way to save humanity and defeat Dhaos, just as their parents did before them.
Every year that passes, the lifeblood known as mana which sustains the world of Sylvarant slowly ebbs away. The land itself is dying, fields are turning barren, and life itself is on the brink of collapse. In the quiet country town of Iselia the last remaining hope, the Chosen of Martel, begins the Journey of World Regeneration – a quest which, if completed, would renew the world’s supply of mana and bring prosperity once more. However, Colette is not the first chosen to attempt the Journey; many have already fallen before her. Along with the mercenary Kratos and the half-elf school teacher Raine, Colette must travel to each of the elemental shrines and release the seals so that the regeneration can begin.
These two OVA both derive from RPGs. Just as the games are similar, the animes are in various ways; presence of magic, sword fighting, etc. Even the characters match: Cless (phantasia) and Lloyd (symphonia) are sword users that will protect others no matter what; Mint (phantasia) and Colette (symphonia) give the same feeling of "holyness".
So most likely if you've liked one, you might want to watch the other (and why not play the games to get the whole story)