I have created some punching animations that I am pretty happy with but to create them I used the body_ctrl bone on the default mannequin to pivot into the punches. I would like to use layered blend per bone so the legs can walk forward while the top half punches but currently the entire body pivots with the punches. Is there I way I can fix this, or do I need to redo the anims without using the body_ctrl bone?
A video and the current layered blend can be found here Imgur: The magic of the Internet
You first need to create a new slot. To do that, navigate to the Anim Slot Manager window from any animation asset (if you don’t see that on the bottom right, you can open it from the Window menu) and create a new slot.
After that, right click on an empty space inside your anim graph, search for “default slot” on the menu that pops up and select "Slot ‘DefaultSlot’ ". Once it’s placed, head to the Details window while the slot node is selected and change the slot to the newly created one from the dropdown menu under the Settings section. Then connect it’s input (Source) pin into an animation, blend space or a locomotion and connect it’s output pin into the Blend Poses 0 pin of the Layered Blend per Bone node.
Finally, head to the Details window once again while the Layered Blend per Bone node is selected, click on the plus (+) icon next to the Branch Filters section under Config > Layer Setup and insert the exact name of your desired bone into the text box next to Bone Name (the animation will affect the bones with a lower hierarchy than the bone you choose)
Hope this helps! 
This does not appear to work, as body_ctrl does not seem to be part of the actual skeleton
That’s how you’d split the body to play different animations at the same time 
Why would you wanna split the body from that control element (which you can’t because it’s not a bone) or the parent of it (which is most likely root) anyway?
Like I said, you should insert the exact name of a bone that you wanna split the body from into that text box next to Bone Name.
Oh and you might wanna switch the Base Pose and the Blend Pose. The slot stays as it is though. So the animations that you wanna play on the upper body should be connected to the slot the slot node should be connected to the Blend Poses 0 pin, and the animations that you wanna olay on the lower body should be connected to the Base Pose.