Enchantment â Aura
Enchanted creature gets +1/+1 and has lifelink.
When Squire's Devotion enters the battlefield, create a 1/1 white Vampire creature token with lifelink.
You need a creature for Squireâ€™s Devotion to target as you cast it. Thereâ€™s no way to have it enter the battlefield attached to the Vampire token itâ€™ll create.
If the creature this Aura would enchant is an illegal target by the time Squireâ€™s Devotion tries to resolve, the Aura spell doesnâ€™t resolve. It wonâ€™t enter the battlefield, so its ability wonâ€™t trigger.