Defenders of Humanity

When this enchantment enters, create X 2/2 white Astartes Warrior creature tokens with vigilance.
{X}{2}{W}, Exile this enchantment: Create X 2/2 white Astartes Warrior creature tokens with vigilance. Activate only if you control no creatures and only during your turn.

Warhammer 40,000 Commander

When Defenders of Humanity enters the battlefield, create X 2/2 white Astartes Warrior creature tokens with vigilance.
{X}{2}{W}, Exile Defenders of Humanity: Create X 2/2 white Astartes Warrior creature tokens with vigilance. Activate only if you control no creatures and only during your turn.

X in the first ability is always calculated separately from X in the second ability, even if you activate second ability in response to the first ability.