How to Get Secret Units in Roblox Eternal Tower Defense

Ever felt like your Roblox Eternal Tower Defense lineup was missing a bit of je ne sais quoi? Well, fear not, for there be hidden treasures aplenty – secret units, if you will – waiting to be unearthed.

In this guide here, we’ll reveal the mystery behind how you can get your hands on secret units in Eternal Tower Defense game and transform your defense from a mere barricade into an unstoppable fortress.

Also check out the new best units in Roblox Eternal Tower Defense, Eternal Tower Defense guide for more latest updates and patch notes.

Secret Units in Roblox Eternal Tower Defense
By Komplex Studio

The Secret Units in Roblox Eternal Tower Defense

In the world of Eternal Tower Defense, there are technically three secret units, plus an event secret unit that we’ll discuss later. To get your hands on these hidden gems, you’ll need to tackle the challenging Eternal challenge modes.

But don’t worry, I’ve got the scoop on where to find each of them.

Event Secret Unit

First off, let’s talk about the event secret unit. To acquire this one, you’ll need to take on the Invasion mode. I highly recommend teaming up with other players on Discord or in-game because the odds of finding this unit are significantly better when you’ve got allies.

During Invasion runs, you have a 5% chance of obtaining the event secret unit. But you can also earn it by collecting 500 of the crystals, which you can then exchange in the Invasion shop.

This unique unit is the only one among these secret units that allows you to do this. It’s a game-changer, so keep this one in mind.

Vegeta, Arlong, and Rukia

Now, let’s get down to business and find out how to obtain the remaining three secret units, Vegeta, Arlong, and Rukia.

These units are obtained by conquering the challenge modes of specific Eternal levels.

  • Vegeta: You’ll find Vegeta in the Namek challenge mode.
  • Arlong: Look for Arlong in the Arlong Park challenge mode.
  • Rukia: Seek out Rukia in the Seoul City challenge mode.

The catch is, you won’t get them easily. Each wave you complete in these challenge modes gives you a mere 0.1% chance of obtaining these units.

So, if you want to maximize your chances, you’ll need to push your defenses to wave 51, where you’ll have a 5.1% chance to snag these rare secret units.

Be warned, obtaining these units can take quite some time and dedication. For example, Vegeta may join your team at level 10, while Arlong might follow shortly after.

However, it took me a staggering four and a half days of relentless grinding and only after I was able to add Rukia to my team. So, patience is key!

What Do These Units Do?

Now that you know where to find these secret units let’s talk about what makes them so special and how they can enhance your tower defense experience.


Vegeta starts as a line attacker, but as you upgrade him, he transforms into a full AOE unit, much like Rolu. Here’s a breakdown of his stats:

  • Max Damage: 14,700
  • Range: Impressive
  • Cool Down: 5.1 seconds

When you’re first starting out in the game, Vegeta is a great unit to have. He can help you sail through a variety of areas, including solo city, due to his massive AOE damage.


Arlong, on the other hand, is the second most expensive of the two units. His unique feature is his giant attack circle. Here are some key stats:

  • Max Damage: 15,000
  • Range: Large
  • Cool Down: 5.1 seconds

While Arlong’s stats are impressive, some players prefer Vegeta due to his earlier AOE transformation, making him more effective in various scenarios.


Rukia brings an interesting twist to the table with her freezing ability. Starting as a line attacker, she eventually evolves into a powerful AOE unit. Here’s what you need to know about her:

  • Max Damage: 22,000
  • Range: Massive
  • Cool Down: 9.8 seconds

Rukia’s wide attack range and the ability to freeze enemies can be a game-changer, especially in specific zones like solo city.

The Event Secret Unit

Now, let’s talk about the event hidden unit. This is a top-tier unit in the game and getting it is well worth the effort. These figures show it:

  • Max Damage: 22,000
  • Range: 7.6
  • Cool Down: 5.3 seconds

This unit can deal out a tonne of damage, and you should consider adding it to your squad because of its burn ability. While it’s slightly harder to get than some awakened LR units, its power and versatility make it a top choice for event and solo city missions.

In conclusion, there are four secret units in Eternal Tower Defense. The event secret unit is the most difficult to obtain, but it is also the most powerful. The other three secret units can be obtained by completing the challenge modes of specific Eternal levels.

If you’re looking to add some extra power to your team, I highly recommend trying to get your hands on one of these secret units. They’re worth the effort!