Zero forma build.

Condition Overload - We apply 5x status effects always due to 100% status proc with chance at doubling them for 600% more damage.
Drifting Contact - Maintain the combo counter while boosting status application chance.
Carnis Mandible - Tri-fold reason. Produces more slash damage against raw hp, increases our status application chance, and if we are hit with a status affliction, and due to it's 2x hits with heavys at a decent base speed there is a good chance with our counter in high numbers we will clear it while gaining immunity to them.

Heat Viral Slash combination destroys pretty much everything.

Summary:

Crit chance is too low to bother with, push the status into double status while maintaining the combo counter to unleash hell once max'd with a fast heavy attack x2. Base speed with Drifting becomes managable and allows you to move through mobs quickly.

Harder mode things switch Melee Prowress with Healing Return will require a Forma to do so.