Universal Tower Defense X Z Update 4.0 Guide, New Unit, Codes & More!

Universal Tower Defense Z has officially launched its massive Update 4.0, bringing one of the biggest content expansions the game has received so far. The update introduces brand-new game modes, 24 new units, unit skins, extraction gameplay, summer content, raids, relics, UI improvements, quality-of-life changes, and several free redeem codes for players. If you’re wondering what Update 4.0 adds and which features are worth checking out first, here’s everything included in this major release.

• Also check out our Universal Tower Defense Codes & Tier List for more rewards!

New Unit Skin System

One of the biggest additions in Update 4.0 is the long-awaited Skin System. Unlike simple cosmetic recolors, these skins completely change a unit’s appearance while also modifying its blessing visuals. Skins are divided into five rarity tiers:

• Secret
• Mythic
• Legendary
• Epic
• Rare

Players can obtain skins from Skin Crates or special shops. Every crate comes in two versions:

• Free Crates purchased using in-game currencies
• Premium Crates purchased with Robux

Two skin collections debut with this update:

• Contest Skin Crate
• Summer Skin Crate

These include exclusive skins for units such as Ancient Shinobi, Triple Threat, Crow Shinobi, Phantom Captain, Virtual Idol, Bulmo, Mimicry Sorcerer, and many more.

New Extraction Game Modes

Update 4.0 introduces Extraction, an entirely new gameplay style that differs from traditional tower defense stages. Instead of defending a single path, players explore large maps, complete objectives, encounter random events, battle powerful bosses, and safely extract before losing their rewards. Extraction supports both solo and multiplayer play.

Team Cost System

Before entering an Extraction Stage, players build their loadout using a new Team Point system.

Each player receives 100 Team Points.

Unit costs include:

• Universal / Boundless – 35
• Secret – 25
• Exclusive / Mythic – 15
• Legendary – 5
• Epic – 3
• Rare – 1

Some featured event units cost zero points.

Players can also swap units during certain sections of an expedition.

Life Stock System

Extraction introduces three Life Stocks.

Failing regular stages removes one stock.

Losing a boss battle immediately consumes all remaining stocks.

Extraction System

After defeating bosses, players must successfully reach an Extraction Zone.

Missing the extraction or failing the extraction battle causes every reward earned during the run to be lost.

Golden Palace Extraction Stage

Golden Palace is the first Extraction map introduced in Update 4.0. Players explore the palace while completing objectives that unlock the final boss.

Exclusive rewards include:

• Phantom Stealer Relic Set
• Trickster
• Wild Card
• Evolution materials

Unique mechanics include:

• Stealth gameplay
• Shadow patrols
• Hidden encounters
• Locked treasure rooms
• Elite enemies
• Optional mini-bosses
• Velvet Room challenges

Players can even choose an early extraction if they prefer keeping current rewards instead of risking everything against the final boss.

Phantom-tagged units also cost zero Team Points inside this mode.

Crime Fighting Extraction Stage

The second Extraction mode takes players into a superhero-inspired city where they complete various missions while tracking dangerous villains.

Objectives include:

• Defeating criminals
• Pizza deliveries
• Investigating villain activity
• Completing world events
• Fighting mini-bosses
• Battling the final Symbiotic Alien boss

Exclusive rewards include:

• Human Spider
• Iron Billionaire
• Symbiotic Alien
• Hero Relic Set
• Evolution materials

Hero-tagged units cost zero Team Points while playing this mode.

Summer Event

The Summer Event introduces two playable modes:

• Act 1
• Infinite Mode

Players build teams using a point-based system similar to Extraction while new Summer units can be used for free.

Every four waves players receive buff cards that help counter newly introduced enemy types.

Mini bosses appear every five waves before a final boss closes the event.

Rewards include:

• Summer Currency
• Gems
• Gold
• Summer Capsules

Hollow Destroyers vs Reapers Event

This new team-based event lets players choose one of two factions:

• Hollow Destroyers
• Reapers

Players contribute points toward their faction by:

• Clearing stages
• Defeating enemy bosses
• Using team abilities

Winning teams receive bonus rewards every three days.

The event introduces:

• Light Prince
• Soul War Currency
• Evolution materials
• Team-exclusive abilities

New Story and Raid Content

Several additional stages have also been added.

Moonless Sky Universal Tear

This stage introduces a challenging three-phase battle against Ichiko.

Players can obtain:

• The King
• Evolution materials

After evolving The King, players can unlock the new Boundless unit The Almighty.

Reaper City Raid

The latest raid rewards include:

• Flame Captain
• Almighty Relic Set
• Soul Reaper Badge Currency

Beast Desert

Beast Desert includes:

• Story
• Legend Stage
• Virtual Realm

Players can obtain:

• Drill Hero (Spiral)
• Heaven Piercer Relic Set
• Multiple evolution materials

All New Units in Update 4.0

Update 4.0 introduces 24 brand-new units across multiple rarities.

Boundless Units

• Moonless Sky
• The Almighty

Secret Units

• Drill Hero (Spiral)
• Ice Queen (White Haze)
• Flame Captain (Ember)
• Light Prince (Ascension)
• The King
• Human Spider (Responsible)
• Iron Billionaire (Genius)
• Symbiotic Alien (Apex)
• Trickster (Phantom)

Unrivaled Unit

• Visionary (Unrivaled)

Exclusive Units

• Ashen Valkyrie (Ignition)
• Azuron (Wrath)

Mythical Units

• Cat Captain (Lightning)
• The Terror (Ascension)
• Bloody Captain (Healer)
• Zombie Apostle (Ascension)
• The Fatality (Ascension)
• Visionary (Inspired)
• Cranium (Phantom)
• Anne (Phantom)
• Feline (Phantom)

New Synchro Drives

Two new Synchro Drives are available.
Mechanical Spider
Fusion of:

• Human Spider
• Iron Billionaire

Symbiote Spider
Fusion of:

• Human Spider
• Symbiotic Alien

New Relic Sets

Four new relic collections have been added.

Heaven Piercer Set

Available from Beast Desert Story and Virtual Realm. This set focuses on increasing damage when nearby allies are present while improving buff effectiveness.

Almighty Set

Dropped from Reaper City Raid. Its bonuses revolve around doubled buffs, stronger damage-over-time effects, and powerful bonuses for King, Villain, Hollow Destroyer, and Royal Guard units.

Phantom Stealer Set

Earned in Golden Palace. This relic enhances boss damage, summon strength, AoE size, elemental damage, and Phantom-tag units.

Hero Set

Obtained from Crime Fighting. The Hero Set significantly boosts debuff duration and damage while providing strong bonuses for Hero-tagged units.

Major Quality-of-Life Improvements

Update 4.0 modernizes several core systems. Highlights include:

• Magic and Physical Unit Types
• Completely redesigned Unit UI
• New Inventory interface
• Relic rerolls directly from inventory
• In-game relic swapping before matches
• Better relic stat tracking
• Revamped Quest system
• Separate Normal and Shiny indexes
• Guild Leaderboards
• Secret Banner selection
• Water God returns
• Unit Storage increased from 250 to 300
• Relic Storage increased from 600 to 700

New Enemy Types

Seven new enemy types appear during the Summer Event.

They include:

• Ranged
• Hopper
• Reviver
• Necromancer
• Camouflage
• Brute

Each introduces unique mechanics that encourage players to build more specialized teams instead of relying on a single strategy.

New Team Abilities

The Hollow Destroyers vs Reapers event introduces purchasable battlefield abilities.

Global abilities include:

• Damage Buff
• Farm Income Boost
• Stun Immunity
• Boss Immobilization

Faction abilities include:

• Hollow Destroyers Deals massive boss damage while disabling boss mechanics.
  
• Reapers Deals heavy area damage while increasing damage taken by enemies.

New Events

Several limited-time activities are available alongside Update 4.0. These include:

• Summer Event
• Soul Ascension Quests
• Hollow Destroyers vs Reapers Quests
• Expedition Event Quests
• Trickster Trial

Meanwhile, Battle of the Strongest and Flames and Waves events remain available.

New Cosmetics

Players can also unlock additional cosmetics.
Mounts

• Royal Wings
• Mantis Ray

Emotes

• Pickle Aura
• Sword Release

Universal Tower Defense Z Update 4.0 Codes

Here are the latest active codes released with Update 4.0.

• ReaperVsHollowDestroyers 50 Trait Rerolls, 10,000 Gems
• SpectacularSpider! 50 Trait Rerolls, 100,000 Universal Gems Season 1 Part 1
• TheGuyFromSmash! 50 Trait Rerolls, 100,000 Universal Gems Season 1 Part 2
• Summer2026! 50 Trait Rerolls, 10,000 Summer Currency

New Bundles

Five premium bundles have been added to the shop.

They include:

• Reaper vs Hollow Destroyer Bundle
• Imaginary Bundle
• Zombie Bundle
• Hollow Destroyer Bundle
• Reaper Bundle

These packs contain combinations of exclusive mounts, emotes, rerolls, Gems, Gold, Universal Gems, and other valuable resources.

Final Thoughts

Universal Tower Defense Z Update 4.0 is one of the game’s largest updates to date, introducing far more than just new units. The new Extraction game mode delivers a fresh gameplay experience, while the Summer Event, faction battles, raids, skins, relics, and extensive quality-of-life improvements give players plenty of reasons to return. With 24 new units, four free redeem codes, multiple endgame activities, and expanded progression systems, Update 4.0 offers a substantial amount of new content for both veteran players and newcomers alike.