As long as The Wandering Emperor entered the battlefield this turn, you may activate her loyalty abilities any time you could cast an instant.
[+1]: Put a +1/+1 counter on up to one target creature. It gains first strike until end of turn.
[–1]: Create a 2/2 white Samurai creature token with vigilance.
[–2]: Exile target tapped creature. You gain 2 life.