Rerolling is one of the most resource-intensive systems in Universal Tower Defense Z, but it is also the most impactful for unit optimization. Whether you are chasing the elusive Ruler trait (0.1% chance) or optimizing relic substats, understanding when to reroll, what to target, and when to stop is essential. This guide covers both trait rerolling and stat rerolling strategies.
Trait Reroll Basics
Trait rerolling assigns a random trait from the pool to a unit. Each roll costs Trait Reroll tokens, and the result is completely random with no pity system. The trait pool and their probabilities are:
| Trait | Roll Chance | Effect | Best For |
|---|---|---|---|
| Ruler | 0.1% | +200% DMG, -20% CD, +30% RNG, 1 limit | Main DPS |
| Astral | 0.45% | +20% Affliction Duration, -20% SPA | Control units |
| Sacred | 0.3% | +25% Damage, +25% Range, -10% SPA, -15% Cost | Expensive units |
| Duelist | 0.8% | +35% Boss damage, +25% Crit rate, +20% Range | Boss fights |
| Fortunate | 1% | +20% Income for farm units | Farm units |
| Wizard | 1.5% | +15% Elemental DMG, -10% SPA | Elemental DPS |
| Prodigy | 2% | +30% DMG, +10% Crit rate, -5% CD | General DPS |
Expected Rerolls Per Trait
| Trait | Probability | Average Rerolls Needed | Worst Case (95th percentile) |
|---|---|---|---|
| Ruler | 0.1% | ~1000 | ~3000 |
| Astral | 0.45% | ~222 | ~666 |
| Sacred | 0.3% | ~333 | ~1000 |
| Duelist | 0.8% | ~125 | ~375 |
| Fortunate | 1% | ~100 | ~300 |
| Wizard | 1.5% | ~67 | ~200 |
| Prodigy | 2% | ~50 | ~150 |
Trait Reroll Priority by Account Stage
Your reroll budget determines which traits you should chase. Here is the recommended priority at each account stage:
Early Game (0-500 Rerolls)
Focus on achievable traits with high impact:
| Priority | Unit Type | Target Trait | Why |
|---|---|---|---|
| 1 | Farm unit | Fortunate (1%) | Economy boost pays for all future rerolls |
| 2 | Primary DPS | Prodigy (2%) or Wizard (1.5%) | Decent DPS boost with achievable odds |
| 3 | Support | Any trait is fine | Support benefits from any stat boost |
Mid Game (500-2000 Rerolls)
| Priority | Unit Type | Target Trait | Why |
|---|---|---|---|
| 1 | Primary DPS | Sacred (0.3%) or Duelist (0.8%) | Significant damage boost |
| 2 | Farm unit #2 | Fortunate (1%) | Double income generation |
| 3 | Support | Astral (0.45%) | Extended buff/debuff duration |
Endgame (2000+ Rerolls)
| Priority | Unit Type | Target Trait | Why |
|---|---|---|---|
| 1 | Primary DPS | Ruler (0.1%) | The ultimate DPS trait — +200% DMG |
| 2 | Hill DPS | Sacred or Ruler | Cost reduction for expensive hill units |
| 3 | Boss Specialist | Duelist (0.8%) | Maximize Raid boss damage |
How to Farm Trait Rerolls
Trait Rerolls come from multiple sources. Prioritize the highest-yield methods:
| Source | Rerolls Per Hour | Effort | Notes |
|---|---|---|---|
| Challenges (Daily) | 100-150 | Active | 30% drop rate per completion |
| Infinite Mode AFK | 8-16 | Passive | Reroll Cube conversion |
| Daily Quests | 30-50 | Active | Quick daily completion |
| Codes | Varies (50-200) | Instant | Check codes page |
| Events | 100-500 | Limited | Seasonal and milestone events |
| Story Mode | 10-20 | Active | Low rate — farm Gems instead |
The most efficient approach is running daily Challenges (100-150 Rerolls) plus AFK Infinite Mode (8-16 Rerolls overnight). Combined with codes and quests, you can save 250+ Rerolls per week. See our traits guide for more farming details.
Stat Reroll Guide (Relics)
Stat Rerolls optimize relic substats. Unlike trait rerolls, stat rerolls can use Stat Locks to protect good substats while rerolling bad ones.
Stat Reroll Priority
| Relic Slot | Main Stat (Keep) | Substats to Chase | Substats to Reroll |
|---|---|---|---|
| Top | HP, Range | CD, Damage, Crit | HP regen, useless stats |
| Bottom | CD, Damage, Crit Rate | Crit DMG, Range | HP, defense stats |
| Accessory | Elemental DMG | CD, Crit Rate | HP, defense stats |
Stat Lock Usage
Stat Locks are limited and precious. Use them only on:
| Priority | When to Use Stat Lock | Example |
|---|---|---|
| 1 | Top main stat + 2 good substats | Fused Warrior Bottom with CD + Crit + bad 4th |
| 2 | 3 good substats + 1 bad | Bottom with CD, Crit, DMG + bad 4th |
| Never | 1 or fewer good substats | Reroll without locks — not worth saving |
Check our relics guide for complete BiS stat recommendations per unit role.
When to Stop Rerolling
The biggest mistake players make is spending too many rerolls chasing marginal upgrades. Here are clear stop rules:
| Current Trait | Stop If You Get | Do Not Chase Further |
|---|---|---|
| Prodigy | Sacred or Duelist | Ruler (not worth 1000+ rerolls) |
| Wizard | Duelist or Sacred | Ruler on non-primary DPS |
| Fortunate (farm) | Stay with Fortunate | Never reroll a Fortunate farm unit |
| Duelist | Stay with Duelist | Ruler on non-boss specialists |
| Sacred | Stay with Sacred | Ruler only on primary DPS |
The expected value of rerolling a good trait for a slightly better one is almost always negative. Only chase Ruler on your primary DPS — every other unit should keep a B-tier or higher trait.
Reroll Budget Calculator
Use this table to estimate how many Rerolls you need to save:
| Goal Trait | Average Cost | Monthly Savings | Months to Save |
|---|---|---|---|
| Fortunate | 100 Rerolls | 250/week | < 1 month |
| Prodigy | 50 Rerolls | 250/week | < 1 month |
| Duelist | 125 Rerolls | 250/week | < 1 month |
| Sacred | 333 Rerolls | 250/week | ~1.5 months |
| Astral | 222 Rerolls | 250/week | ~1 month |
| Ruler | 1000 Rerolls | 250/week | ~4 months |
Advanced Tips for Experienced Players
Once you have mastered the basics, these advanced strategies will help you optimize every aspect of your UTDZ gameplay:
Daily Optimization Checklist
| Time | Activity | Expected Reward | Time Investment |
|---|---|---|---|
| Login | Redeem any new codes | 10-200K+ Gems | 1 minute |
| Morning | Complete 3 Daily Quests | 30K Gems + 50 Rerolls | 15 minutes |
| Morning | Run 3 Challenges | 50K Gems + 100 Rerolls | 20 minutes |
| Midday | Farm Story Mode | 300K+ Gems per hour | 1+ hour |
| Evening | Run Raids (if available) | Shards + Relics | 30-45 min |
| Overnight | Set up AFK Infinite Mode | 80K+ Gems per hour | 5 minutes to set up |
Resource Management Framework
| Resource | Daily Income | Weekly Income | Recommended Reserve | Spending Rule |
|---|---|---|---|---|
| Gems | 500K+ | 3.5M+ | 5000+ (for featured banner) | Save for pity, spend on Evolution |
| Trait Rerolls | 150+ | 1050+ | 500+ (for trait chase) | Fortunate first, then chase best trait |
| Mythic Shards | 3-5 | 21-35 | Always spend on S-tier | Etherealize primary DPS first |
| Exclusive Shards | 0-1 | 3-6 | Save until 5 | Only spend on primary S-tier |
| Secret Shards | 0 | 1-2 | Never spend frivolously | Primary S-tier only |
| Stat Locks | 0-1 | 2-5 | 5+ | Only use on BiS relics |
Weekly Planning Template
| Day | Focus | Secondary | Gems Target |
|---|---|---|---|
| Monday | Daily Quests + Challenges | Story Mode farming | 500K |
| Tuesday | Daily Quests + Raid day | Evolution material farming | 400K |
| Wednesday | Daily Quests + Story farming | Trait Reroll farming | 600K |
| Thursday | Daily Quests + Challenges | Relic farming (Raids) | 500K |
| Friday | Daily Quests + Raid day | Featured banner pulls if available | 400K |
| Saturday | Intensive Story Mode farming | AFK setup for overnight | 1M+ |
| Sunday | Weekly Quests + Review | Plan next week, check codes | 500K+ |
Common Mistakes to Avoid
| Mistake | Impact | Fix | Prevention |
|---|---|---|---|
| Spreading shards across multiple units | No unit reaches full power | Concentrate on primary DPS first | Follow etherealization priority order |
| Rerolling DPS traits before Farm Fortunate | Missing 20% income for weeks/months | Always get Fortunate first | Roll Farm trait before DPS |
| Spending Gems on standard banner | No pity guarantee | Save for featured banner only | Track featured banner schedule |
| Skipping daily quests | 30K+ Gems + 50 Rerolls lost per day | Do all 3 daily quests every day | Set a daily alarm or routine |
| Over-investing in B-tier units | Wasted resources that should go to S-tier | Minimal investment only | Stop at Evolution 1 for B-tier |
| Not joining co-op Raids | Missing Exclusive/Secret shards | Join Raid groups via Discord | Schedule weekly Raid sessions |
| Forgetting to AFK farm | 80K+ Gems/hour lost overnight | Set up AFK before sleeping | Make it part of bedtime routine |
Frequently Asked Questions
Is there a pity system for trait rerolls? No, UTDZ trait rerolling has no pity system. Every roll is independent with the same probability. You could theoretically roll Ruler on your first try or never.
Should I reroll my farm unit off Fortunate for Ruler? Absolutely not. Fortunate is the best trait for farm units. The +20% Income boost compounds over every wave. No other trait provides more value on a farm unit.
Can I transfer traits between units? No, traits are permanently bound to the unit they are rolled on. You must reroll the specific unit.
What is the most efficient way to get Rerolls? Daily Challenges at 100-150 Rerolls per session, plus AFK Infinite Mode for passive Reroll Cube income. Check our gems farming guide for the complete resource farming schedule.