This will add 20hp/tic to any poison, not just make it 20 hp/tic. however, the regen is still active, so poisons that are 1 hp/tic will just seems to be 20hp/tic.
Latent effect
Active while poisoned.
The latent applies to STR +5, not the additional effect. The Additional effect: Poison has a 100% proc; there is no need to actually be poisoned.
Hidden effect
While poisoned, drains 20 hp/tick.
This stacks with both the Regen effect on the weapon and Poison effect. A Venom Potion (-5HP/tick) effectively becomes -24 HP/tick.
I love this weapon when inside nyzul isle. u can pull without fear of getting agro from puddings/gears if u were to use provoke. The regen is nice in nyzul as well if u stack it with ulthalam's ring since there is no time for resting. if you get poisoned just switch to something in ur ammo slot and u wont lose tp. must have for wars that join shout nyzul fights