The Berserk stance and Focus Energy spell/ability gives me no indication as to what will happen when I use it. Perhaps this is intentional though. The Rage attack works fine however.
They do exactly what they say on the tin, basically. They have descriptions on the learn screen, but when you go to use them, it only shows their effects - in Berserk's case, it puts you into a Berserk stance, and in Focus Energy's case, it restores mana and stamina.