Check displacement in your render seting.
THE BEST WAY TO USE THE PRODUCT:
Voila, your monster is ready
The hand of M4 is locked for the arms figure. For easy use, use poses already made.
If you want to adjust for example the position of the leg, remember to select the M4 leg and not the leg figure.
To use it down the parameters panel (click on the left top arrow and select body part) or hierarchy window