This is actually old news as it's been in pre-release from 7/10 (which means only people who already have an account can play right now) with the actual release coming in just less than 2 weeks.
What is Alteil?
Alteil is, as it describes itself, a story-driven online browser-base ccg. You choose a starter, play a few matches, get new cards and slightly get better and better at it.
Alteil has 4 spheres or factions, each has a level that can be raised during a match (using sp). All have a certain specialty though they can always go outside of their usual style.
-Refess (Yellow): Buffs, self-heals and sturdy units, some benefit from dawn or noon time of day.
-Lawtia (Purple): Sp-draining, graveyard manipulation, a lot of them benefit from night time.
-Gowen (Red): Straight-forward damage and rank-up (buffs that activate once you have a certain sphere lvl)
-Falkow (Blue): Crowd control, return and high speed.
Each player has access to a 3*3 field where he can place units. Using the units you summon, you have to defeat the opponent's army and take down his life points. Beware though, as doing so activates soul skills which can turn the tide of battle.
One of the biggest draws of Alteil is the art, which is drawn by a number of well-known artists of Gundam, Code Geass and other fame. While this means the style varies from card to card, it also means that each card is an artwork in its own right.