Vigilance is a special ability in Magic the Gathering Tactics.
A figure with vigilance counterattacks against every attack.
Vigilance is defensive protection against multiple enemy attacks.
When combined with first strike, a figure with vigilance can be problematic for enemies to deal with.
Vigilance works differently in the Magic card game than it does in Magic Tactics.
While the spirit of the ability is the same, the mechanics turn out very differently.
In the Magic card game, vigilance allows creatures to attack and still defend.
In Magic Tactics, the attackers go first (unless the figure also has first strike).
Since the mana cost is based on the Magic card game, vigilance is less powerful in the Magic Tactics game.