Once you begin to cast an exiled card, losing control of Kheru Mind-Eater won’t affect the spell.

The last ability of Kheru Mind-Eater only lets you cast cards exiled by that card. If Kheru Mind-Eater leaves the battlefield, the exiled cards are lost forever.

If another player gains control of Kheru Mind-Eater, that player can see all of the exiled cards and may play them. Once a player looks at a face-down exiled card, that player may look at that card any time later in the game.

You must pay the costs to cast the exiled cards. If one has an alternative cost, you may cast it for that cost instead.

You may play land cards exiled with Kheru Mind-Eater only if you have an available land play this turn.