Order of the Spire is a Unit.
How to Get Edit
|•||On Play:||"Awaiting your command."|
This card is most vulnerable during the turn it is summoned, especially if it's early in the match. There are many cards that deal 1 damage to a unit. To minimize risk, keep it in your hand until you start your turn with 3 power, then play it, then use a 4th power to activate its effect.
The effect retains temporary amounts, less the initial buff. For example, if this card is (1ATK/1DEF) and you play a spell that gives this card "(+4/+4) this turn" it temporarily becomes (5/5), then Empower (10/10), and when your turn ends (10-4/10-4)=(6/6).