I killed Aery.

So I was playing Mordekaiser and running Aery (as I had learned all ally-cast abilities send her to shield, and Mord's W counts) and about 10 minutes in I ult Kayle, Aery goes to attack, I score the kill as Aery is returning, get a ghost... and from that point on Aery is gone. At least, until the 27 minute mark where after respawning, she mysteriously respawned with me. I spent 20 minutes without my keystone. Sad times were had.