The [Praedos] has many passives and perks that allow you to save mod spaces and tends to push towards a hybrid x12 combo build, which means you spend the majority of your time spamming light attacks to build combo mixed in with heavy attacks at x12 combo against heavy units such as demolishers, acolytes, bosses, eximus units etc. With priming, a x12 heavy attack is strong enough so that single heavy attack can cause a steel path demolyst to bleed out.
UPDATE JULY 2024
With health and armor changes, slash has been relatively nerfed while raw damage has better TTK, particularly if you end up using a viral heat or corrosive heat primer. Melee Influence allows you to spread non impact/puncture/slash status effects in a 20m radius, after being activated by electric status. This effectively allows you to clear maps fast. For single target damage, use [Primed Fever Strike] over [Shocking Touch] and Melee Duplicate.
UPDATE DEC 2023
For a more light attack focused build, use Melee Duplicate, you want to sit around 137% critical chance to maximise the damage from melee duplicate. This means you should NOT slot [Sacrificial Steel] or a riven with +cc. This is because Melee Duplicate triggers on any tier 1 crit but the duplicated hit has a chance to be a tier 2 crit. This means you want slightly higher than 100 CC with a balance of low enough CC that tier 1 crits happen but high enough CC that enough Tier 2 crits occur on the second hit. The formula for maximising the final multiplier can be found by CC = (3 x CD - 4)/(2 x CD - 2). At 5 crit damage we get 137.5% CC. If you add cold status (from [Epitaph] priming for example), we get 5.5 crit damage which gives 139% CC. If we add [Dreamer's Wrath], we get 6.14 for 140% CC. Rank 10 [Blood Rush] + [Gladiator Might] hits 130cc and every puncture status adds 5cc until 155cc. This means you will be floating within the right range depending on puncture procs.
For a more x12 heavy oriented Tennokai build, use Melee Animosity to get an additional +420% CC, giving a total of 302% final CC or guaranteed red crit on heavy.
Evolution I : Incarnon mode - heavy attack at 5x combo to transform into Incarnon mode, where you will receive a passive +40% attack speed and +2 range. This basically allows you to drop attack speed and range mods on the melee.
Evolution II: Whirling Fury - additional +20% attack speed to bring total of +60% attack speed without mods OR Drifting Grace for sprint/slide if you prefer the mobility boost.
Evolution III: Shockwave Synergy - gain 4 combo for each enemy hit by a slam attack. Helps regain combo quicker, particularly on the last attack of forward block combo of Soverign Outcast.
Evolution IV: Evolved Ascension - +30% parkour velocity. Gives a good boost to bullet jump.
Evolution V: Universal Readiness - 5 combo on ammo pickup. This allows you to keep at x12 combo at all times even when predominantly using guns. Kinetic Harmony is an alternative if you DON'T use Tennokai.
[Sovereign Outcast] Stance: Arguably the most important mod. The neutral light attack combo (Rogue Edict) has a ridiculous average damage multiplier of 859.6%/s, one of the highest in the game (behind [Final Harbinger]) that also has FOUR forced slash procs on every 3rd hit each with a 200% multiplier. The forward block combo (Villain Rule) also has a Slam attack on 4th hit which helps gain more combo via Shockwave Synergy, so you can seamlessly weave in slams into your combos.
[Condition Overload]: +80% damage per status effect. This is NOT capped by the number of unique statuses i.e. with impact, puncture, slash statuses alone you get +240% damage per hit. Paired with a primer such as Kuva Nukor or Epitaph, you can get up to 8 unique statuses for +640% damage per hit.
[Organ Shatter]: +85% crit damage with +60% heavy attack wind up which stacks with Kinetic Harmony for +160% heavy attack wind up speed. Makes your heavy attacks extremely quick.
[Weeping Wounds]: +440% status chance at x12 combo, giving 108% status. This means with each hit you are guaranteed a status (in addition to forced slash status procs from Rogue Edict). Since [Praedos] is 80% slash bias, with every 4 hits of Rogue edict, you will basically get 3 minimum slash procs from status with an additional 4 forced slash status procs from the stance, giving around 7-8 slash status procs which bypass armor to kill Grineer/Corrupted easily.
Blood Rush: +440% critical chance at x12 combo allows crit chance to hit 108%.
[Gladiator Might]: Gives an addition +110% crit chance at x12 combo to hit 130% crit chance, as well as an additional 60% crit damage on top of 85% from organ shatter to hit 4.9x crit multiplier.
Quickening: Gives a total of +100% attack speed with passives and combo gain. This is flexible for a riven or sac steel.
Primed Smite Grineer/Corrupted: double dips slash DoT to give 2.4025x more damage.
Melee Elementalist: boosts status damage by 90%
Shocking Touch: adds electric of Melee Influence and boosts elec DOT by 90%.
Discpline's merit: consistently gives tennokai every 4 hits, can also use [Dreamer's Wrath]
For Corpus: Swap [Shocking Touch] for [Primed Fever Strike] (to make pure toxin to bypass shields)