Cyclone

 is an active skill that can be learned by Berserkers at level 2 and is able to be ranked up at later levels. Number of times the skill can be charged and the amount of damage dealt both varies dependent on skill rank.

can be performed with an axe by the Berserker to deal AoE damage. It is useful the way AoE skills are useful: it can damage multiple enemies at once, and its large damage area makes it easy to hit the opponent. However, if you are confident of hitting your opponent, it is recommended to use instead.

Cyclone does make your character move forward a bit.

Like other skills that require charging, gets stronger the longer the player holds down the skill button. Attaining Rank III allows the player to move at half speed while charging. Attaining Rank IV allows the player to go into Overcharge when charging too long; this will continuously deal significant amounts of damage to the character.

Cyclone gets significant damage boost with Apex. It's improved with new passive skill Eye of the Storm that creates possibility that skill resets and can be cast again immediately without charging it up again. Cyclone damage also increases on each reset. It almost doubles on second cast, and raises slower after that.

Rank table
To upgrade to the next rank, one must pay a certain price of gold dependent on rank.

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.)