Exosister Pax

“During the Main Phase: Pay 800 LP; add 1 "Exosister" card from your Deck to your hand, except "Exosister Pax", then, if you added a monster by this effect, you can Special Summon it if the other "Exosister" monster mentioned on it is on your field or in your GY. You can only activate 1 "Exosister Pax" per turn.”