These twin daggers, the signature weapons of a very bulky boi codenamed the Wolf (not the Wolf of Saturn Six, wrong wolf), possess a unique neutral combo, launching four fireballs in quick succession at the location of the mouse cursor when they are fired. Unfortunately, these fireballs have a measly multiplier and can only inflict Impact and Heat procs. You will most likely be spamming forward combo with the Nepheri.

Corpus Build

Unfortunately, the innate heat prevents easy access to anti-Corpus elements, so your "Corpus Build" is going to be a different weapon.

ALTERNATIVES

Primed Smite: normal Smite
Primed Reach: [Spring-Loaded Blade]. Normal [Reach] is a rather meager increase.

WHY [Carnis Mandible]?

Never heard of Slash? The status effect inflicts DoT (Damage over Time) with True damage. True damage ignores armor, making it unparalleled in ending the lives of Grineer. [Carnis Mandible] is used to increase the bias of Slash damage, thus increasing the chance of inflicting the Slash status. [Weeping Wounds] further increases Status Chance based on your Combo Counter, even giving it a chance to inflict two statuses.

BUT ISN'T HEAT GOOD?

Heat is still affected by armor. Thus, the potential damage of it becomes far, far lower against Grineer and Corrupted specifically. Feel free to keep burning Infested, though. I heard roast Infested is on the crunchy side, according to [Grendel].
NOTE: This statement is in relation to Steel Path. Regular Star Chart can be cleared with anything.