Updated 2026-05-17 - independent UTDX guide
Universal Tower Defense X Relics Guide
UTDX relics guide: how relics work, relic rerolls, best relic picks per unit role, and how to manage the Relic Reroll currency. Practical advice from 50+ hours of UTDX testing.
Relics Guide quick answer
Relics in Universal Tower Defense X are passive upgrades applied to individual units. Active codes include 25 or more Relic Rerolls: redeem 40kInterestedWano! and Update2.75! before you start manually rerolling. Prioritize relics that match your unit's role (burst relics for boss-killers, sustain relics for supports). Do not stack multiple single-purpose relics on a farm unit.
What relics are in Universal Tower Defense X
Relics are passive stat upgrades slotted onto individual units in UTDX. Each unit can hold one or more relic slots depending on its rarity and upgrade level, and the relics you assign stay active throughout the entire wave run. Because relics scale with the unit's own damage and role, the correct relic for King Sailor is not the same as the correct relic for Water God or Bulmo.
The relic pool includes effects in several categories: damage amplifiers that increase base or burst output, fire-rate boosters that tighten attack intervals, range extenders that let a unit cover longer lane segments, and support relics that modify aura strength, slow duration, or economy output. Knowing which category applies to your unit's job is the most important filter before any reroll decision.
One of the most common misreadings is treating relics as a second upgrade track that should always be maxed. Relic slots that match the unit's role add clear value. Relic slots that contradict the role: a fire-rate relic on a farm unit, for instance: often change a number without changing results. I check role alignment before spending any Relic Reroll currency.
How relic rerolls work
Relic Rerolls are the currency used to cycle through the relic pool for a specific unit slot. Each reroll randomises the relic type and value within the pool for that unit. The outcome is not guaranteed on any given roll, so Relic Rerolls should be treated as a probabilistic improvement: meaningful over many uses, but capable of producing unhelpful results on a short run.
Active UTDX codes are the fastest source of free Relic Rerolls. As of May 2026, 40kInterestedWano! gives 25 Relic Rerolls and Update2.75! gives 25 Relic Rerolls as well. Redeem both before starting any manual reroll session. Spending earned gem currency on Relic Rerolls is also an option, but the code batch should be claimed first to avoid paying for currency you can get free.
Set a stop condition before rerolling. Decide which relic type and approximate stat range you are targeting, then stop once the current result meets or exceeds that condition. Rolling past a good result because a better outcome is theoretically possible is the same loss pattern seen in banner decisions: the perfect result displaces a useful result and leaves the account with neither.
Best relics for boss-killer units
Boss-killer units: First Emperor, Alpha Devil, The Strongest in History, Nutaru, and similar burst carries: benefit most from relics that increase their damage output or reduce their attack interval during boss contact windows. A damage amplifier relic on First Emperor or Alpha Devil directly extends the burst they deal while the boss remains in range. A fire-rate relic produces a similar effect but through more frequent attacks rather than higher per-hit damage.
Range extender relics are situationally useful for boss killers because they allow the unit to enter its firing window earlier in the boss path. On maps like Ant Island and Void Court, where the boss enters range near a specific choke point, a modest range extension can add two or three additional attack cycles per pass. On shorter contact maps, the same extension provides little benefit.
What boss killers should avoid is support-category relics: aura range, slow duration, economy output: that address roles those units do not fill. A 100-gem upgrade to a support relic slot on First Emperor is a 100-gem diversion from improving its burst window. Keep relic choices specific to the unit's intended job and check placement before concluding that a relic is underperforming.
Relic priority for support and farm units
Support units: Virtual Idol, Love Goddess, Mimicry Sorcerer: carry relics that extend or strengthen their team effects rather than their personal damage numbers. Aura radius relics let a support's team effect touch more surrounding units. Aura strength relics increase the buff magnitude applied to each unit inside the radius. The choice between radius and strength depends on your build geometry: a crowded placement benefits more from strength; a spread placement benefits more from radius.
Farm units such as Bulmo and Fastcart benefit from economy relics that increase their gold output rate or shorten their income interval. An economy relic on Bulmo can effectively accelerate the account's upgrade schedule for the entire run. The tradeoff is that farm relics produce no combat value, so economy relics on a unit assigned to a combat slot waste both resources.
Utility units like Water God and Ice Empress suit control-duration relics that extend the slow or crowd-control window applied to enemies. A longer slow duration on Water God means enemies remain inside your carry's firing range for more attack cycles, which translates directly to higher effective DPS from the surrounding team: even though Water God's own damage stat does not change.
Relic reroll efficiency and code timing
Relic Reroll efficiency improves when you target one unit and one relic category per session rather than rerolling multiple units at once. Spreading rerolls across a full roster in one session means each unit gets fewer targeted attempts, which reduces the probability of hitting the specific type and value range you identified. Single-unit reroll sessions with a defined stop condition use currency more predictably.
Code timing interacts with reroll efficiency because the code batch from a single update can cover a full targeted reroll session on a boss killer. The 25 Relic Rerolls from 40kInterestedWano! plus the 25 from Update2.75! total 50 rerolls. On a unit where the target relic type appears in roughly one of every four outcomes, 50 rolls gives a strong probability of hitting the type. Combine that with a reasonable value threshold: not the maximum possible stat, just the range that meaningfully improves the unit: and the code batch often delivers the improvement without requiring purchased currency.
One final note: relic rerolling is not the most urgent upgrade task for new accounts. Establishing the right role mix, placing units correctly, and reaching Wave 50 consistency should come first. Relic optimisation is a refinement step that adds meaningful value to an already functional build, not a foundation for a struggling one.
FAQ
What are relics in Universal Tower Defense X?
Relics are passive stat upgrades assigned to individual unit slots. They can increase damage, fire rate, range, aura strength, or economy output depending on type.
Which codes give Relic Rerolls in UTDX?
40kInterestedWano! gives 25 Relic Rerolls and Update2.75! gives 25 Relic Rerolls. Redeem both before spending currency on manual rerolls.
What is the best relic for First Emperor?
A damage amplifier or fire-rate relic that increases burst output during boss contact windows. Avoid support-category relics on boss-killer units.
How many Relic Rerolls should I use per session?
Set a stop condition first: a target relic type and acceptable stat range: then stop once the result meets it. Rolling past a good result is a common waste pattern.
Can I use relics on farm units like Bulmo?
Yes. Economy relics on farm units increase gold output and accelerate the upgrade schedule. Avoid combat relics on units assigned to economy roles.