It's the dark equivalent of the starter dragon. As such, it is good! Keep it, level it, use it.
On that note, I got an Ivory Dragon from a Rare Pull just a little bit ago. I now have five full teams!
-Team Tricolor: Earth Guardian, Big Flamie, Big Bubblie, Flame knight, Aqua Fighter
-Team Water: Plesiel, Blue Goblin, Sapphire Carbuncle, Water Pengdra, Aqua Fighter
-Team Dark: Loki, Gryps Rider, Black Fighter, Baddie (I should probably evolve this guy...), Blood Devil
-Team Grass: Earth Guardian, Goblin, Emerald Carbuncle, Big Woodsie, Ogre
-Team Light: Ivory Dragon, Gryps Rider, Topaz Carbuncle, Big Shinee, White Fighter
Good enough for now, I can't wait to finish the "second tier" dungeons and start leveling up everyone.