You’re grinding Infinite Mode, the wave count is creeping past 100, and suddenly your placement strategy feels like it's made of paper. We've all been there. But then you see someone drop a unit that looks familiar, yet different—it's got that "X" tag. If you’ve spent any time in the All Star Tower Defense (ASTD) community lately, you know that the "X" variants aren't just fancy reskins. They are the meta-shifters.
Honestly, the "X" codes or variants are basically the game's way of breathing new life into older, legendary characters that fell out of favor. Think of it as a prestige system that actually works. You take a unit that used to be the GOAT in 2021, apply the X-evolution, and suddenly they’re hitting for millions. It’s a power creep, sure, but it’s one that rewards the players who have been hoarding units since the early days of the Roblox hit.
What Are ASTD X Codes and Variants?
Let’s get the terminology straight first because it gets confusing. When people talk about "X codes," they're usually referring to the specific evolutionary path or the redemption codes that sometimes drop during major updates to give out the materials needed for these units. In the actual game logic, an "X" unit is a separate tier. They aren't just 6-stars or 7-stars; they are technically reimagined versions of classic characters like Goku (Kakarot), Naruto (Uzuma), or Sasuke (Uchiha).
Why does it matter? Because the damage scaling is astronomical.
Take the Kakarot (Ultra Instinct) X variant. If you're comparing it to the standard 6-star version, the range increase alone makes it a mandatory pick for leaderboard pushes. The developers at Top Forest are notorious for tweaking these numbers behind the scenes, so what works today might be slightly nerfed tomorrow, but the X-tier has consistently remained the gold standard for high-level play.
✨ Don't miss: Breath of the Wild: Why the 2017 Game of the Year Still Matters Today
The Evolution Process: It’s a Grind
You can't just wish these units into existence. You’ve gotta work for them. Usually, this involves a "Star Pass" or very specific trial rewards. Most players get stuck on the "X-Evolution" requirements. To get most of these, you need a base unit at level 100 or higher, plus a specific amount of "X-Fluids" or "X-Essence."
It’s expensive. Really expensive.
I’ve seen players burn through 50,000 gems just trying to get the secondary materials required for a single X-unit. But is it worth it? If you’re trying to clear the latest Raids or get into the top 100 of the seasonal leaderboard, you don't really have a choice. The gap between a standard 7-star and an X-variant is often the difference between wave 150 and wave 250.
The Breakdown of Top-Tier X Units
- Kakarot (Ultra X): This is the big one. His AoE (Area of Effect) is massive. When you fully upgrade him in-game, his final "Godly" strike covers almost half the map on smaller stages.
- Uzuma (Sage X): If you need crowd control, this is your guy. His slow effect is actually meaningful, unlike the standard slow units that get bypassed by fast enemies in later waves.
- Uchiha (Eternal X): Known for the burn damage. In ASTD, Damage Over Time (DoT) is often the only way to kill bosses with billions of HP.
The Secret Meta: Why Some "X" Units Fail
Not every X unit is a winner. This is the part most YouTubers won't tell you because they want the clickbait "NEW OP UNIT" title. Some X-variants are actually worse for your economy. For example, some of the older "X" experiments had such high placement costs that you could never actually get them to their final form in a standard match before getting overwhelmed.
It’s all about the efficiency ratio.
You want units that provide high DPS (Damage Per Second) per dollar spent in-game. If an X-unit costs $100,000 to max out but only does 20% more damage than a $50,000 unit, you’re better off bringing a support unit like Erwin or Blackbeard to buff your cheaper towers.
How to Get X Codes and Materials Fast
Everyone wants the shortcut. In ASTD, the shortcut is timing. You need to keep an eye on the official Discord and the Twitter (X) accounts of the developers. They drop "X" specific codes during milestone events—like 2 million likes or a major anime anniversary.
These codes often give:
- Stardust (The most valuable currency for X-summons).
- X-Essence (Used for the actual evolution).
- Gold and Gems (Standard, but necessary for leveling the base unit).
A common mistake? Using your Stardust on the regular banner. Stop doing that. If you want the X-tier units, you have to save every single bit of Stardust for the "Special" banners that rotate every few days. The pull rate is abysmal—usually under 1%—so if you aren't going in with at least 500-1,000 Stardust, you’re basically just gambling your time away.
Pro Tips for Managing Your X-Team
Don't fill your whole deck with X units. It sounds tempting, but you'll go broke in wave 10. You need a balanced deck.
Ideally, your setup should look like this: one or two high-DPS X units, one money maker (like Speedwagon or Bulma), one or two slow/stun units, and a buffer. If you try to run Kakarot X and Uzuma X together, you'll find that by the time you afford the first one, the enemies have already leaked past your base.
Also, pay attention to the "Blessings." Some X units can be equipped with specific items that further multiply their stats. An X-unit with a "Godly" blessing is basically a cheat code. It turns a difficult Raid into a walk in the park.
The Future of X Variants in 2026
The game is evolving. We’re seeing more "X" variants being added every month, and the power level is only going up. Some veterans are worried that this makes old units useless. They're kinda right. But that’s the nature of gacha games. If things didn't get stronger, we’d all stop playing.
The next big shift? Rumor has it we might see "Dual X" evolutions where you combine two different X units. Imagine a fusion unit that takes the range of one and the DoT of another. It would break the game, but honestly, ASTD is at its best when it's a little bit broken.
Actionable Steps for Your Next Session
If you’re ready to start building your X-tier roster, don't just start clicking buttons. Start with the Kakarot path; it's the most stable and has the highest ROI (Return on Investment) for new players.
First, make sure your base unit is fed with enough fodder to hit level 100. Then, go to the "Evolve" menu and check exactly which items you're missing. Don't waste gems on random pulls—wait for the specific "X-Material" trials to appear in the rotation. These trials are hard, so you might need to find a team in the lobby to carry you through the first few runs.
Lastly, check your settings and make sure "Auto-Sell" isn't on for rare units. You’d be surprised how many people accidentally delete the base unit they need for an X-evolution because they weren't paying attention during a mass summon. Pay attention to the labels, save your Stardust, and focus on one unit at a time. Trying to evolve three X-units at once is a fast track to burnout.