As Frontier Siege enters the battlefield, choose Khans or Dragons.
• Khans - At the beginning of each of your main phases, add {G}{G} to your mana pool.
• Dragons - Whenever a creature with flying enters the battlefield under your control, you may have it fight target creature you don't control.

• Number: 150
• Rarity: R
• Type: Enchantment
• Mana cost: 3G
• Color: Green
• Artist: James Ryman