Rule 700.5a

A player’s devotion to each color and combination of colors, taking into account any effects that modify devotion, is calculated after considering any copy, control, or text-changing effects but before any other effects that modify the characteristics of permanents. This is an exception to 613.10. See also rule 613, “Interaction of Continuous Effects.” Example: Altar of the Pantheon is an artifact with no colored mana in its cost and an ability that says “Your devotion to each color and each combination of colors is increased by one.” Purphoros, God of the Forge is a permanent mana cost {3}{R} and an ability that says “As long as your devotion to red is less than five, Purphoros isn’t a creature.” If a player controls both of these permanents and another permanent that costs {R}{R}{R}, that player’s devotion to red is calculated to be five before Purphoros’s type-changing effect is applied, and Purphoros is a creature.