EVOLUTIONS
Evo 2: Swordsmanship's Flourish gives +30 base dmg and 100% combo count chance
Evo 3: Resolute Force gives 10s combo duration
Evo 4: Subtle Force boosts both CC and SC, which improves the overall slash procs from both light and heavy attacks at x12 combo.
MOD BREAKDOWN
[Condition Overload]: Gives +80% dmg per status effect for up to +320% dmg after 4 status effects, although note this has a slight reduced effect on Reaping Spiral stance multipliers (approximately 60% effective atm).
Organ Shatter: mandatory CD. We no longer need Amalgam version due to Tennokai.
Blood Rush: mandatory +440% CC at x12 combo.
Weeping Wounds: mandatory +440% SC at x12 combo.
Primed Reach: allows you to hit more enemies per swing
Primed Smite: double dips on slash and heat DoT, multiplying slash DPS by 2.4025x
[Berserker Fury]: boosts attack speed by up to 70%, flexible for [Quickening] or Primed Fury. Can drop entirely if offloading from ability (e.g warcry, redline) or from arcane (e.g. arcane strike).
Gladiator Might: flexible but boosts CC by another +110% and CD by 0.6.
Melee Animosity: boosts heavy CC by 420% CC after swinging light attacks
[Discipline's Merit]: gives guaranteed Tennokai every 4 light attacks, for best consistency in achieving x12 heavy attacks. Flexible for [Dreamer's Wrath] which gives a similar degree of Tennokai activation with slightly less consistency, but slightly more final crit dmg.
RIVEN
Positives: Crit Damage, Attack Speed, Range. If you roll range, slot over [Primed Reach].
FRAME SYNERGIES
If using [Kullervo] with 1, consider swapping [Primed Reach] out for [Primed Pressure Point] since you mostly hit just one enemy and spread that damage via curse. We can stack +dmg from [Primed Pressure Point] because [Condition Overload] ignores the +dmg boost of Swordsmanship's Flourish as well as some of the stance multiplier from [Reaping Spiral].
If using with [Ash], can use Melee Crescendo for x12 heavy spam