How can I get this effect?

Custom vinnieyte. Link the opacity of it with health maybe?

A cheap way is to use a umg the size of the screen and bind its opacity value.

Health at 100% = 1

So got to use some math to get the difference so opacity would be 0 at 100 and .9 at 10%

So that’d be like opacity = health float minus max health?

1-1=0 opacity
1-.9=.1
1-.5=.5 ect