It's time to talk about Verore's most feared character card. Not Aether Acolyte. Not Siphoner. Not even the dreaded Hydra or Demon of Fear.
Master of Demons.
When deployed, this meager 1/1 gets a +3/+3 buff for every demon you have in play. Ridiculous, I know. Incredibly overpowered, but as telegraphed as playing any other creature.
Unless you tutor up your Master of Demons with Evellee. When the Mage Guild Recruiter sends the Master to your support zone, no matter how many demons you have in play they're a mere 1/1. Easy pickings. EXCEPT for the fact that when you move that Master of Demons to a combat zone they get the buff that they would normally get on deploy.
There are a few implications here: first of all, you can lose demons in between tutoring and moving. But more importantly, you can play more demons between tutoring and deploying, getting more bang for your buck. And, because the master only looks like a 1/1, they'll often be ignored by enemy calculations until it's too late.
I don't know if this interaction is intended or not, but it happens to me all the time. Maybe because my main deck in constructed is an Evellee/Hellkeeper deck. Maybe not. You decide. At any rate, when my 1/1 became a 10/10 seemingly out of the blue today surprising my opponent, I decided that it was past time that I announced this interaction to the world so everyone can beware of this interaction. You probably won't see it often, but when you do now you'll know what happened.