Mafia 90. The Tale of Oldforest.

0. The 3rd Berserker's Fury skill triggers on the Warlord. A test of vigilance. (Displayed if it removes a block). Potion of protection against blocking - Herbalist. (Displayed).

I think it's better to upgrade the Berserker. After healing the immune unit, I wouldn't be surprised if the Herbalist also visits the Warlord when he's not in his right mind. It's better to anticipate such a scenario in advance than to rack your brains later...