ALL MY BUILDS FOCUS ON USING UNDEAD-THEMED WARFRAMES WITH WEAPONS FITTING THEIR THEMES. THEY MAY NOT BE THE ABSOLUTE BEST OPTION FOR WHAT I USE THEM, BUT I STILL MAKE SURE THEY'RE MORE THAN VIABLE ENOUGH.

[Xaku Prime] represents the Skeleton.

INTRODUCTION

This build focuses on making [Xaku Prime]'s entire set work while also being able to use The Vast Untime to destroy all breakable objects in a tile for quick resource collection. To do this we follow these steps:

0. Invert [Xaku Prime]'s abilities so you only have to tap on The Lost to cast it. Made sure it's hovered over [Gaze] out of the three abilities. Also make sure you have a bright emissive colour for Rest & Rage to give the damage vulnerability debuff. If you want your frame to have a dark colour aesthetically youc an always choose that as the secondary emissive colour and the ability will still use the day form.

1. Cast Hardened Wellspring for energy regeneration and wait until Molt Efficiency is at 36%.

2. Cast The Vast Untime for free to freeze all other timers. Recast Hardened Wellspring whenever you feel your energy is running low.

3. Find some enemies, cast Grasp of Lohk, and just enjoy killing everything around you. Whenever The Vast Untime is about to run out recast it. If you need to armour strip just cast The Lost and let your stolen weapons shoot everything down. If you need some extra damage, just cast Rest & Rage on top of that.

4. Whenever you're in a room with lots of breakable objects like crates just cast The Vast Untime to break them all. Chances are with Inner Might and [Mystic Bond] you'll be able to cast it for free, and if somehow none of them are active you will have more than enough energy to cast it anyway.

BUILD SPECIFICS

FOCUS SCHOOL

We use Zenurik for this build. The nodes we care most about are:

• Energy Pulse: This makes sure we end up getting 50% more energy per energy orb we pick up, letting us fill up faster.
• Inner Might: This gives us a free ability cast every minute, which is around the same duration The Vast Untime has, so we'd cast it for free most of the time.
• Wellspring: This gives us +5 energy per second, so we don't need to worry about ever running out.

ARCHON SHARDS

• Crimson Archon Shard:
  +15% Ability Duration x3. With +45% ability duration from this and +36% ability duration from Molt Efficiency we'll end up with 203.5% ability duration. This means The Vast Untime will end up lasting for 50.9 seconds.

• Amber Archon Shard:
  +37.5% Casting Speed x2. We mainly care about the cast speed of The Vast Untime, both to break stuff quickly and to lose as little duration on other abilities as possible. 2 shards is always a nice spot cast speed wise. Otherwise if the cast speed isn't an issue these could be more duration or strength to replace our arcane.

STATS:

• STRENGTH: We use [Power Drift], [Transient Fortitude], [Umbral Intensify], [Augur Secrets], and Arcane Crepuscular. This is mainly to armour strip with The Lost. You need 200% ability strength to armour and shield strip. We could replace [Power Drift] or [Augur Secrets] for something else and use Hardened Wellspring instead, but it's more tedious than this setup. Arcane Crepuscular only works while invisible, so if using a non-invisible setup it'd have to be replaced with two tauforged crimson archon shards or another arcane that boosts ability strength.

• DURATION: We use [Primed Continuity], Molt Efficiency, and three archon shards. While duration affects all of our abilities, the only ones we care about are Rest & Rage and The Vast Untime. As mentioned before, with our current setup they'll last 44.8 and 50.9 seconds respectively.

• RANGE: We use [Overextended], [Stretch], and [Augur Reach]. We want over 250% ability range for Grasp of Lohk to give us 15 weapons. It also affects the radius of all our other abilities.

• EFFICIENCY/ENERGY: We use [Flow]. [Flow] gives us a bigger pool of energy to fill up with our focus school, and the free casts of our focus school and companion make sure we don't run out fast. [Primed Flow] can be used, but it'd cost one more forma and honestly I've never really been short of energy to the point I've felt the extra 200 or so will be needed.

LOADOUT:

Unlike most of my builds, in this case the loadout is mostly optional, since we're focusing on killing with our abilities only. Nonetheless, here's my loadout.

• PRIMARY: We use the Nataruk. Honestly this weapon is so good you don't really need to forma it at all. The only issue one could have with it is that it's more single-target oriented.
  I chose this weapon thematically because it's made out of Sentient bones, and a skeleton archer is a very common archetype.

• SECONDARY: We use the Laetum. This is an insane secondary. The incarnon mode used to double dip with Xata's Whisper but that's not the case anymore. Out of all our weapons this would probably be our main damage dealer if we wanted to hit things by ourselves.
  I chose this weapon thematically because it's a void-infused weapon just like Xaku Prime.

• MELEE: We use the Prisma Skana. a pretty nice influence weapon, not much to say besides that.
  I chose this weapon thematically because skeleton swordsmen are pretty iconic, the [Prisma Skana] was infused with void energies, and the Kintsugi skin for it takes a broken version and repairs it by mending it together, all characteristics that fit Xaku Prime.

• COMPANION: We use Shade Prime. The choice for invisibility is between this and the [Huras Kubrow]. Why we chose the sentinel instead is because it can refill our shields as extra protection and the Duplex Bond clones can spread viral nicely with a Tazicor.

GAMEPLAY ELEMENTS:

• SHIELD GATING: We use [Brief Respite], [Augur Secrets], and [Augur Reach]. Since the ability we'll use the most will be The Vast Untime this will give us 100 x (1.5 + (0.4 x 2) = 230 energy per cast.
  The reason why we want shield recharge is because of how shield gating works. when your shields are depleted you gain invulnerability depending on how much shields you had before it went down to 0. the calculation depends on how many shields you have. If you have more than 53 it's ((Current Shields/350) ^ 0.65) + 1/3. With our current setup we get ((230/350) ^ 0.65) + 1/3 = 1.09 seconds of invincibility in the worst case scenario. If we build up shields to go over 1150 or more we'll end up with 2.5 seconds of invincibility.
• SURVIVABILITY: We don't really have space for any survivability mods, but while The Vast Untime is active [Xaku Prime] passively dodges 75% of all damage, while our companion will keep us invisible as long as we don't shoot or swing weapons.

HELMINTH OPTIONS

Why are we replacing Xata's Whisper? Sure, [Xata]'s whisper double dips on faction mods and headshot damage, but Xata's Whisper DOES NOT AFFECT GRASP OF LOHK IN ANY WAY WHATSOEVER. Since this build focuses on killing with Grasp of Lohk while remaining invisible, then Xata's Whisper becomes useless. If you don't use an invisibility setup and use your weapons then free free to keep it, since it's a great ability.

Now as for options besides Rest & Rage:
Roar is the obvious one, since it actually buffs Grasp of Lohk It does less damage than Rest & Rage overall, but it's a cast and be done until the timer runs out, while Rest & Rage only affects the area you cast it on.
If you don't wanna summon clones of your sentinel with [Duplex Bond] then you can use Wyrd Scythes to spread viral instead, but the number of enemies and amount of stacks will be lower.
And if you don't care about damage but are worried about AoE attacks or toxin eximus killing you indirectly you can use Spellbind to become immune to any status including knockdown.

BONUS BUILD - 0 FORMA OPTION

So, if you want to test this build but are too worried that you won't like it and will waste forma on it, here's a 0 forma version of the build for you to test. 0 Forma builds always have to make some compromises, but I try to make them as close to the original to give an accurrate representation when testing.

MOD CHANGES:

• [Brief Respite] to Energy Siphon: We have a different polarity, so we use this instead to lower the strength requirement for full armour strip.
• Power Drift removed: It'll be replaced below, and we don't have enough capacity to add any exilus mod and fill out our mod slots.
• [Transient Fortitude] to [Blind Rage]: Because of the polarities and capacity we end up needing way more ability strength, so we gotta take the efficiency loss.
• [Umbral Intensify] to [Amar's Hatred]: This replaces the exilus slot from before, leaving us with the same amount of ability strength as a regular build.

And that's it! Besides changing the aura, removing a mod, and downgrading two all the mods are exactly the same. While all our abilities cost considerably more to cast, the build should be pretty much the same, with duration being a bit longer..