What is the new Frenzy status effect in Monster Hunter 4 Ultimate? What does it do? What causes it? How can it be avoided?
The Hunter becomes infected with a virus. It requires time to incubate, represented by a purple bar filling up below the Hunter's on-screen name. If the bar fills completely, the virus negates natural health recovery, meaning that the Hunter takes full damage from attacks without being able to heal back half of it. Additionally, all attacks which would cause the condition will deal extra damage while the virus is active. However, if the Hunter inflicts enough damage on a monster whilst the virus is incubating, they gain a 15% Affinity boost instead, as well as an immunity to infection for a short period of time.
While incubating, the incubation can be delayed by consuming a Nulberry. The fully incubated virus can only be cured by prolonged exposure to a Panacea or waiting it out.
I can confirm this information is correct. The Gore Magala and Shagaru Magala are the primary monsters that deal this status effect. Additionally, infected monsters (ie. Infected Tigrex) will gain the ability to deal this status effect.
If the virus fully incubates and you get the debuff, it's easier to simply run to another area. The debuff should go away after a minute. Attempting to fight the monster with the incubated virus is a death wish, as many attacks do extra damage. A recent fight against Shagaru Magala showed me just how many attacks can one-shot me under this debuff.