Not sure if it is intended, but World in Pain (Fury Staff) followed by a skill switch to Tai Chi Sword and Heaven's Sword increased the player's health by a huge %.
Edit: this is not just with Fury Staff anymore. There appears to be a glitch with taichi sword that gives a huge amount of health. I understand that the skill gives health, but this glitch is giving more health than intended.
A few players have been using this and it is unfair if it is not intended.
i have screenshots of player using the glitch. let me know if you want to see it GM.