The answer you are looking for… Go into the blueprint editor, find the control you want to invert on your character… say for example “Mouse Axis Y” Or “Controller Axis X” (It may be named something different depending on your naming system…
You will see an node linked from the controller, to the character being controlled by this axis… Usually it says “Axis Value” and is linked to a value in the character input.
What you need to do, is insert a float*float node in between these two and make the number -1.
Now the reason for this, is because the mouse axis are each numbers. A number multiplied by 1 remains the same number, unless you multiply it by -1 then it becomes inverted. So when you multiply the axis(which is a float) using a float*float node by -1, you effectively invert the mouse axis.
See Image
