Skaldic Rage is the first core enhancement in Warchanter tree, of the Bard class.
Description: Expend a Song to fly into Rage, granting you a +4 Rage bonus to Strength and -4 penalty to AC. When Skaldic Rage ends you become Fatigued. Requires 4 trained ranks in Perform to use.
Skaldic Rage lasts for 60 seconds initially. Duration starts at 3 minutes and increases with effects that increase Song durations.
Notes:
Training the Skaldic Rage enhancement has a (probably) unintended effect on Barbarian Rage: The strength bonus granted by your barbarian rage is increased by 4. Skaldic Rage does not need to be active (just trained) to produce this effect. Activating Skaldic Rage along with barbarian rage grants no additional benefit (though your armor class is decreased by additional 4).
Enhancements from the Barbarian prestige trees, e.g. Ravager's Hardy Rage do not increase the effect of your Skaldic Rage.
Instant activation like Barbarian Rage.
Counts as a Rage effect for the purposes of Fury of the Wild.
http://ddowiki.com/page/Skaldic_Rage(tested soon after enhpass, see talk page; behavior might be different now)