I created a build to concentrate on his Celestial Twin and on synergy with his Cloud Walker and Defy skills.
We replaced his stick with Eclipse (with augment) because this exalted weapon is currently one of the worst in game, literally every single melee weapon exceed it.
Because Celestial Twin is affected only by Strength I decided to only add three Umbral Mods which give me 177% Strength, that mean 3.54x Health multiplier for our Clone. And it is worth to mention that Twin and Weapons he uses are affected by [Wukong]'s equipped Mods. That mean that our Brother is the most powerful Specter in the whole game! Twin also has 2x (damage multiplier).
Cloud Walker and Defy is affected by Strength, Range and Duration, so I tried to combine mods in a way that does not hurt any statistics, and at the same time increases the Efficiency of both skills. By doing this, I have increased Strength and Duration (more than doubled).
Thanks to that Cloud Walker's Health regen is 1.77%/m (Health restore affects Twin, Kubrows, Kavats, and MOAs, but has no effect on Sentinels) and it last for 4.72s. Because I did touch Range a bit it has 7.28m stun radius. That skill also has 30 m/s (cloud movement speed), 100% (status cleanse on cast), 2s (stun duration). And it cost only 25 Energy. Use it. Use it a lot.
Worth to mention... Cloud Walker does not trigger defenses like Sensor Bars, Laser Barriers, and Security Cameras. Cloud Walker can pass through Spy vault's defenses without triggering an alarm.
Defy taunt enemies into attacking [Wukong] and his Twin. This skill is very useful on higher levels. It has 13.28x (damage multiplier), 2.66x (armor multiplier - capped at 1500 armor), 4.72s (invulnerability duration), 59s (armor duration), 10.92m (staff swing radius), -50% (move speed penalty), 100% (status cleanse on spin).
Ability Synergy: When activating Defy with an active Celestial Twin, the Twin engages in Defy, gaining the same increased Threat Level, invulnerability, damage [Reflection], and armor bonus.
Why [Narrow Minded] is R8? Because I didn't want to put another Umbral Forma and I really wanted to fit [Primed Sure Footed] into this build, this mod helps us a lot, believe me, I was running without it long enough to know that knockdown is really a pain in the ass. A bit crippled Range does affect a little Cloud Walker's Stun Radius and Defy's Staff Swing Radius, but it's nothing too harmful. You should not worry about it.
[Adaptation] is my mod of choice just because I like that mod and how it works. [Wukong Prime] is my current main and I decided to give him one of my Umbra Forma. He is definitely worth it.
Last but not least, [Wukong]'s passive:
[Wukong] has learned five techniques to avoid death whenever he takes fatal damage. [Wukong] will be randomly allowed 3 of these techniques per mission to avoid death 3 times. Each technique will make [Wukong] avoid entering bleedout upon taking fatal damage, invulnerable for 2 seconds, restore 50% health, and provide a unique buff.
Suggested arcanes are Grace and [Guardian].
Use Naramon Focus School for its Power Spike.
If you got problem with Energy, replace [Guardian] with Energize. Or simply use Zenurik Focus School.
It is HIGHLY RECOMMENDED to use Helios (Prime) with his Deconstructor (Prime) as StatStick for Gladiator Mod Set. Three of them will give us +30% Critical Chance, stacks with Melee Combo Multiplier. Don't worry, even if your Sentinel dies, the Set Bonus will remain. DE took it from us.
As for Companion, I recommend Smeeta. Alternatively, You can use undying Panzer Vulpaphyla