An efficiency build to take advantage of the [Pennant]'s passive, because you need to do heavy attacks to trigger it and normal attacks to make use of it. Run with [Swift Momentum] as your aura and Zenurik as your focus school for more efficiency or Naramon to keep your combo longer. [Ash]'s [Rising Storm] augment is also useful for building combo and giving you more duration. Build up to 12x combo, then use a heavy attack, which will give you 46 seconds worth of the attack speed passive, increasing your attack speed by 50% for each enemy killed.

Alternatively, you can swap [Primed Fever Strike] for [Virulent Scourge] and [Weeping Wounds] for various other mods. If want a different aura while using Zenurik, you can use Drifting Contact. If you want more efficiency with Naramon, you can use Reflex Coil. Vicious Frost will let you run Viral/Electric. If you want more mobility, Dispatch Overdrive. As with all melees, change from Condition Overload to Primed Pressure Point for lower-level content where it will allow you to one-shot. Swapping the Naramon polarity for 2 Madurais costs 1 more forma, but will allow you more flexibility with your builds.