Extract and open the file pl0a.udas.lfs inside of BIO4 > EM.
Then copy the file called "pl0a_0_022.eff".
Paste it into your "EFF Tool" folder and extract it.
Open the folder then go into the folder called "Effect 0", open the folder called "Effect Group 21" and open the .txt file inside.
Then you will see 5 Effect entries (Ignore "# Main Effect")
Go down into the first entry "Effect 0" until you see 3 lines: "Color_R" "Color_G" "Color_B"
You will see that these 3 values are the same as all of the others in the different entries. What you want to do is change the RGB value for every entry (You can use Notepad++ too rename every entry at once).
The original RGB values are:
Color_R = 0xE1
Color_G = 0x55
Color_B = 0x69 for every single entry
Make sure every RGB entry has the same values if you want it all to be the same color.
Example:
Entry 0
Color_R = 0x00
Color_G = 0x00
Color_B = 0xFF
Entry 1
Color_R = 0x00
Color_G = 0x00
Color_B = 0xFF
ETC...
You can add multiple colors to the effect by changing each entry individually, though I have not tested this myself.
the Color_A channel is for the Alpha here are some example's
Color_A = 0x00 (0% visibility)
Color_A = 0x23 (50% visibility)
Color_A = 0xFF (100% visibility)
If you wish to make your own values, use this tool:
RGB to HEX
Make sure you convert it into hex if it's on decimal.
After all of that you can repack your eff file and put it in the Udas file again and put it into your game
Note: when putting the pl0a.udas file back into the EM folder make sure that the .LFS version is not present or add a .bak extension after .LFS (you don't need to remove the .lfs file if you have the companion trainer)