I'm probably one of the only people on the planet who's been enough of a mad lad to do this, but I'm about six forma in to Xaku. I've played them a fair bit, experimented with their abilities, and have OPINIONS. That said, I can kinda' get what DE was going for with their kit, and here's the basic synergies I've been able to figure out.
Xaku seems to be built around the idea of weakening enemies to void damage with his 4, and then dealing that damage as a bonus to enemies either through their abilities, such as grasp of lohk, or with weapons while running the Xata's Whisper buff.
That said, in practice... Void damage has a 50% penalty versus cloned flesh, and fossilized enemies. Other than that, it's neutral versus everything. So, I'd say the first important change that's needed is to just make Void a true neutral damage type. This solves the problem of Xaku's kit being 50% nerfed against grineer and infested by default, and also gives us a little more versatility with our operator weapons as a side benefit.
So, on to the abilities.
The first part of Xaku's kit, "Xata's Whisper" is a pretty boilerplate damage buff. It's unironically pretty good, from what I can tell, it's a total damage modifier, not an elemental modifier. So let's say you were going to deal 100 damage, you put on the ability, you deal 126 damage. It also is feedable to the helminth system, which is nice too. You could put this on something like Mesa and give that frame the ability to reset the damage resist of sentients while in peacemaker. People call this ability useless, but it's really not as bad as everyone thinks. The only downside I can think of for this one is because it adds a damage type to your weapon, it can mess with your proc priority if your strength is too high for status builds.
There's a few other issues with this ability too, but I'll get into those later on.
The second part of his kit is "Grasp of Lohk" which, well. Once you know how to use it, this ability is amazing. One thing that's not shown in the tooltip is that this ability has infinite scaling damage. Not only do you gain the ability to grab more guns the more range you have, but the damage of those guns gets directly multiplied by the level of the enemies you stole them from. I run a 200% power strength build, for reasons that will be brought up in the next bit, and let me tell you. This ability melts enemies like you wouldn't believe. A good thing to pair it with is abilities that allow you to group up enemies, like the zaw arcane "exodia hunt" or the operator arcane "magus anomaly." so that you can gather enemies into one spot to guarantee that you'll get the most guns possible.
However, there's some downsides. The duration of this ability is low by default, only 12 seconds, and while it's active, you can't recast it. So if you mess up and only get one gun? You're stuck with it for the duration, or until you jump into a reset pit. So building high duration on Xaku is risky. This ability needs to be recastable. Let us grab more guns and build up to the cap. Having a low base range is fine since grouping enemies is the strategy with this skill, but dear lord does it need to be made recastable. His 1 doesn't give this ability bonus damage, however, but honestly, it doesn't need it.
The third ability is called the lost. It's made up of three parts. Accuse, which is useless and actively hinders your ability to use your 2 to damage enemies, as it will refuse to target things that are temporarily faction swapped to be allies. Gaze, which is f*ckING AMAZING, and Deny, which is a crowd control skill that costs far too much energy to even consider using.
I'm really only going to talk about gaze here. You're going to want to run 200% power strength on this lad, because that gives you a 100% armor reduction. Using things like the zaw or operator arcane I mentioned earlier gives you the power to gather enemies into the defense reduction aura of this ability as well. So here's the combo. Gaze to strip, use a gathering ability, and then either kill em with your weapons, or cast his 2 to get some scaling fun going on with Grasp of Lohk. This ability by far is what defines this warframe's usefulness in late game content, and even steel path farming. The ability to just fully shut down enemy defenses in a set area is mental.
And now for his ultimate. The vast untime.
If you're going to replace any ability on Xaku's kit, make it be this one, because it's f*cking terrible. Where the hell do I even begin on this one.
NOT ONLY does it have a 100 energy casting cost, but while it's active, it drains energy! AND IT HAS A DURATION. This is basically the "Press 4 to lose all your damn energy" button. It's awful. Don't use this ability. It needs either a complete replacement or a buff.
So, what does it do? Well, enemies damaged by your ultimate take 50% extra void damage, and while it's active, you gain a 75% DODGE rate. In practice, this means that one out of every four shots in late game content will murder you. It also is calculated separately from their 25% dodge passive, so you can't stack up to max evasion.
The damaging portion has a line of sight requirement, and in order to give enemies the damage debuff that ONLY INCREASES DAMAGE TAKEN FROM VOID DAMAGE, you need to damage enemies with the ability. It deals void damage, but it doesn't reset sentient damage resistance.
So the energy drain per second, what benefit are you getting that actually justifies it?
Some dodge rate and some extra movement speed. That's pretty much it. If you were to use the ability with base efficiency and base duration, you'd spend 200 energy over 25 seconds to keep this ability active. Xaku has 230 energy without flow, 459 with regular flow, and 650 with primed flow. The cost of this ability makes running either efficiency, or arcane energize, an absolute must have. And honestly, the cost isn't even worth it.
Considering the name of the ability, "The Vast Untime," I'd say that it needs the following to SOMEWHAT justify its cost. While the ability is active? PAUSE THE DURATION OF ALL OF XAKU'S OTHER ABILITIES. You wanna keep your guns from the 2? Done! You want to keep your void damage buff active? DONE! You want to keep that gaze debuff active longer? DONE.
Also, nerf the initial casting cost down please, this skill is okay, but it's not "more expensive than peacemaker" tier.
Xaku's kit is a little hard to work with, but they're pretty amazing once you get around the warframe's quirks and figure out how the abilities all work together. Definitely needs some changes to improve general play, and the 4 is all over the f*cking place in terms of how it works, but all in all, they had a pretty solid launch.
I know I tagged this with BUILD, so here's what I came up with. It's a six forma setup that doesn't use any umbral forma, but does use two umbral mods.
https://i.imgur.com/3sBSzoO.jpeg
Text-wise, here's the basics. Arcane Energize and Arcane Aegis are just there for energy regen and keeping shields up to try and maximize the benefit from adaptation. So far as weapons, I'm running the daikyu/zaw nikana combo for life steal on melees, as well as the ability to get enemies gathered on slam attacks from exodia hunt.
155% duration is a sweet spot that doesn't punish you too hard if you mess up the cast of their 2, 50% efficiency is offset by all the extra energy you get from arcane energize, 235% range is because his abilities REALLY LOVE RANGE, and 200% strength to get gaze to have a 100% armor strip.
Thank you for reading! I had fun writing this up.
External link →