Flurry of Blows

Flurry of Blows is an active skill that can be learned by Berserkers at level 56. It cannot be ranked up.

This skill is now removed as active skill and its effect is merged to.

Flurry of Blows can be performed with an axe by the Berserker to greatly increase damage speed. As the skill description says, this skill will speed up both the attack animation of your skills (ie. your swings are faster) as well as the time it takes to charge up an attack. Be warned that this skill will quite significantly change the timing of your gameplay, as your attacks will connect faster and you would go into overcharge for your charge skills much faster.

According to the description, yes, this skill costs HP instead of MP. Something to keep in mind.

Rank table
is purchased from Tactic Instructors. This skill cannot be upgraded.

Glyphs
To glyph, a glyph must be obtained and learned only once. At level 60, a character has 50 glyph points available to spend on all available berserker glyphs. Most glyphs, specifically common glyphs can be purchased from a Glyph Master, while fine glyphs must be looted from enemies.

(Disclaimer: As NPC shop prices vary depending on a variety of factors, the prices below are subject to variation. Only take them as benchmarks.)