You can use ANY weapon, but the incarnon weapons give the highest possible DPS bonuses, because their evolutions apply to Whipclaw (importantly the fourth evolution).

The best incarnons to use are in this order:
1. [Magistar] Incarnon WITH Magus Aggress Arcane (+300% CD) with Edge of Justice (+100 dmg), Orokin Reach (+1.4 range), Critical Parallel (+16% cc/ +1 cd)
2. Mk-1 [Bo] and [Bo] Incarnon with Stalwart Oak (+90 dmg), Swordsman's Celerity (+20% movement speed), Absolute Dominion (+38% status chance).
3. [Dual Ichor] Incarnon with Alchemist's Wrath (+90 dmg), Resolute Force (+7s combo duration), Absolute Valor (+34% status chance)
4. [Magistar] Incarnon WITHOUT Magus Aggress
5. [Ceramic Dagger] with Breacher's Opportunity (+120 dmg), Orokin [Reach] (+1 range), Absolute Valor (+30% status chance)

Sacrificial Steel is flexible with Buzz Kill.

If you have a good riven, you will slot it over either spoiled strike/[Amar's Contempt] (if riven has + dmg) or [Carnis Mandible] (if riven has +slash).

Preferred riven stats
Wanted Positives : Crit damage > Damage > Crit chance > Slash > Combo Duration
Unwanted Positives : Elements, Puncture, Impact
Wanted Negatives: - Puncture, - Impact or any other harmless negative