In this guide, you will find how to complete Magik Legendary Challenge Demon Child.
The first thing you will need to do is pop the ability to increase your portal damage and then create a portal near the green explosion effect. You need to make sure to point the portal toward the green explosion effect.
After that, aim the guy in the middle and use the card to knock him through the portal. Now you have to use the move one, pick them up and move near the red line.
You need to use your heroic points, so aim at the middle of the icon of the explosion effect and use your heroic point. Press the button and it will do more damage to him by exploding.
After that, kick him into another guy to do extra damage and if you hit him again, you will fail. So you have to use the move-fast lineup with somebody and then hit him again. After getting the card, you need to use the card and it will complete the mission.