If you are taking damage or receiving debuffs but cannot see the monster when in Port Plunder, please run IrisRepair.exe to correct the problem.
If you have an older client installation and do not have IrisRepair.exe in your client folder, you can download the necessary file manually and place it in the data/ folder.
The file you require is
https://noscrubs.net/downloads/client/data/mon_map35a.nss