Support characters focus directly on aiding teammates; vanguard characters are at the front of battle, to act in a combined offensive/tank capacity; offensive characters deal out loads of damage; tanks are durable and soak up lots of damage to protect others; defense focuses on the enemy to indirectly aid teammates. 

Artura: "She is on the front line, making the enemy attack her, not her guild, not her family."

That's the definition of a tank right there, and half of her traits are dedicated to noting how she can take a lot of damage.

Grey does little to actually support the group other than providing shields of shadow illusions. Her main role is to distract, disorient, etc. the enemy through roguish techniques. To be support, she would need to actually support her teammates, which she doesn't; she's the only truly defensive character so far.

She'll participate in the tourney.