Once the shadow has been created, it will try to take control of the target. This is why the shadow fused with the thief's body.
According to records of her performance, the shadow will fuse with the target and tamper with their will. While the heart demon is wrestling control of the body, Monarch Shadow Clone will make her next move.
As usual, her next move was to create another shadow for the target. Then she began controlling this shadow.
Through the Shadow Puppet Metac, everything she made the shadow do was also forced onto the target. So she was controlling the target through the shadow.
These two attacks had impressed Many Eyes because they were trying to do the same thing but from two different directions. One was internal while the other was external, so they were able to work well together nicely.
The Heart Demon Metac tampers with the Will of the target and tries to take control from within. Its effect is subtle and not easily noticeable by the target.
