Strategies: Onslaught

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Wikifender's Note: As of 2021's Spring Forward Update - This strategy guide is outdated. Follow at your own risk.

This page lists recommended builds for use in Onslaught. For information about the game mode itself, see Onslaught.

In the Campaign, the game recommends you use blockades to prevent enemies from reaching your core. This works throughout most of the game and in all Chaos tiers, but Onslaught mode (and Prime Incursions) can feature enemies much stronger than your defenses are used to. This can result in your defenses being overwhelmed very quickly. It's not common for blockades to get destroyed in seconds when you're on a higher level floor, essentially defeating the sole purpose of your blockade.

Because of this, many defenses used in Onslaught differ heavily than those of other game modes; this, sadly, also means that you're more limited on what you can use to defend a lane.

Despite the limitations, there are plenty of different builds you can use, which are listed below. Many of these builds use Shards and Mods - and some builds may even require specific ones to be used.


Poison Dart Tower + Earthshatter Tower

This build can be used very early on, as you already have access to Petrify without the need for any shards or mods. You first want to poison enemies with the Poison Dart Tower (PDT), and then petrify them with the Earthshatter Tower (ES).


  • This build has no required shards or mods, and can be used anytime.
  • The PDT and ES have the longest ranges in the game, which is what separates this build from other Onslaught builds.
  • Cannot be stunned by Cyborks.


  • Both the PDT and ES are towers, which means enemies can destroy them if placed improperly. This also makes the build highly vulnerable to EMP fliers.
  • The PDT's darts can be blocked by Vanguards and/or Geodes (a piercer servo can fix this issue).
  • Can be overwhelmed by large hordes of enemies.


No mods are required, but a shatterquake servo can apply continuous earth damage to a single area, which allows PDTs to instantly petrify enemies in the area of effect.

Defense Range servos can augment the already-impressive range of both towers, so it's highly recommended.


No shards are required. Defense Rate and Deadly Strikes, however, are great augments for any tower, and the PDT and ES are no exceptions.

Earth Toss is a highly recommended shard for your ES. The knock-up provided isn't necessary since you're already petrifying enemies, but this shard also increases the AOE radius of each earth spike, which makes it much easier to petrify a group of enemies. Alternatively, since the ES has the longest range of any defense in the game, stacking Vicious Strikes with Deadly Strikes can make this tower a perfect sniper.

Destruction may seem like a good choice your your PDT's last shard, but you will probably get more benefit from increasing poison damage instead. If you have a spare Vicious Strikes hyper shard, you can stack it with Deadly Strikes to achieve massive range on your PDT if extra suits you more, but you will need 155 stars in Mastery mode to obtain this shard (will be available soon in Prime Incursions).

Reflect Beam + Proton Beam or Weapon Manufacturer

This build can be difficult to prepare, but carries multiple benefits with it when used properly as well as being able to Petrify enemies just as effectively. This is a very common build for players in the hundreds in Onslaught. As such, it is also capable of holding its ground in Prime Incursions.

Strengths (Overall):

  • Cannot be damaged by enemies.
  • Can distract Kobold Fliers and encourage them to dive-bomb to no avail (doesn't work with Kobolts).
  • Using the proper shards/mods can allow this build to defeat Cyborks before giving them the chance to disable anything.
  • Can be adjusted to provide multiple ways to Stun or Slow enemies, and even stack them. This also essentially allows this build to laugh at most lane mutators, like Controlled Burn.
  • Because this build is entirely dependent on nodes, it can vary in cost depending on how many nodes you place. Average cost is around 90 DU with proton beams, or 110 DU with weapon manufacturers.

Weaknesses (Overall):

  • Can be disabled by Cyborks, even when using decent shards and mods (though using them will make the build less likely to be disabled).
  • Cannot tackle every lane mutator. For example, this build suffers heavily against Cursi-kaze.
  • Because of their fast movement speed and immunity to Slow debuffs, Berserker Orcs are notorious for running past this build and will ruin your day if not taken care of quickly.
  • Putting extra range on your Reflect Beams can help to prevent leaks, but the already small range of the torpedo explosions causes range multipliers to be extremely inefficient. Vicious Strikes adds a set amount of range, so it is much more viable for adding range on reflect beams.
  • Requires lots of investment in time and in-game resources to create an effective build.

Strengths (w/ Proton Beam):

  • Usually slightly cheaper than using Weapon Manufacturers.
  • Slows enemies that are in contact with the beam.
  • Can also Freeze enemies if you're using the Frosty Beams shard. The extra stun makes it less likely for berserkers or tanky bosses to leak as well.

Weaknesses (w/ Proton Beam):

  • Requires direct contact with the beam to poison enemies. This is usually mitigated by the beam's ability to slow enemies in contact with it, but the build becomes prone to Cyborks.
  • Depending on where you're building, ranged enemies might not walk into the proton beams. This is most common with Hex Throwers, who love to snipe blockades and/or cores.

Strengths (w/ Weapon Manufacturer):

  • Radiates poison in a decent radius. Deadly Strikes can improve this ability. Large radius also allows your reflect beams to stun Cyborks before they are given the chance to disable your nodes.
  • Produces a weapon for Series EV2 to use.

Weaknesses (w/ Weapon Manufacturer):

  • Slightly more expensive than using proton beams.
  • Doesn't give an additional slow or stun, making it easier for berserkers and tanky bosses to leak.


A poison servo is required on your proton beam or weapon manufacturer in order to apply Petrify to enemies.

A range servo works well on your weapon manufacturer, but poorly on proton & reflect beams.

A Defense Rate servo is required on your Reflect Beams if you do not have a gilded Defense Rate shard. You can skip the shard entirely if you use a 10/10 servo, but it must also be chaos 8 tier to provide enough speed to reach the speed cap.


Despite not being attuned to any element, Reflect Beams will not accept elemental servos. Because of this, Shattering Torpedo is required to make your reflect beams deal the earth damage required to petrify enemies. Unfortunately, Shattering Torpedo is a Chaos 8 shard, so you will most likely have to purchase it.

Maximizing attack speed on your Reflect Beams is a must in order to produce a steady supply of torpedoes to petrify enemies. A gilded Defense Rate shard will bring you to the speed cap, but if you do not have Defense Rate gilded, combining a standard shard with a Defense Rate servo will reach the cap as well.

Reflect Beam torpedoes have an explosion radius of 300 units, which is the same as an Explosive Trap without extra range. Because of its small range, Deadly Strikes will, sadly, provide a poor range modifier. Vicious Strikes is required to add any decent range to your beams, but it requires 155 stars in Mastery mode to obtain. Hyper Shards cost 2 million gold to fully upgrade, but the range cap on Reflect Beams is 800 units (2.67x larger than normal), so you only need a partially upgraded shard to reach this cap (though a fully upgraded one can help resist Cursi-Kaze).

Vicious Strikes is not required; however, your build is more likely to leak enemies without the extra range. A single Cannonball Tower is simple and cheap, but nonetheless effective at cleaning up stragglers.

Anti-Frost Fissures

This is not a generic build for Onslaught, but rather, a build that specializes in wiping out Frost Enemies by utilizing their weakness to fire damage. Flame Auras are also effective, but they don't have quite as much range as fissures do (see below to find out why range is important).


  • Designing your fissures to maximize DPS along with utilizing its ability to deal 2x damage against all frost enemies allows this build to (literally) melt them near instantly, even in very high Onslaught floors.
  • Can also provide decent damage to regular enemies as well.
  • Each fissure/flame aura only requires 30 Defense Units.


  • Frost Orcs can slow your fissures/flame auras if they are close enough, removing a solid chunk of DPS (this is why you want extra range).
  • If Cyborks also appear in the same lane, your fissures are at risk of being disabled if they cannot kill the cyborks fast enough. This can leave the lane extremely vulnerable.


The Anti-Frost servo is essential, hence the fact that this build is specialized for frost enemies. Not only will the servo allow you to deal extra damage to frost enemies, the use of fire damage causes the damage multiplier to DOUBLE along with the base damage!

Either Frost-Boom or Anti-Orc is recommended for your second mod slot. Anti-Orc will help to kill Frost Orcs faster, which can prevent your fissures from being slowed, while frost-boom adds extra overall damage. Use whichever one suits you best.

Defense Range will help even further to prevent Frost Orcs from slowing your fissures.


Defense Rate and Destruction will maximize DPS. You can swap out Destruction with Mass Destruction, but it is not recommended to give up Deadly Strikes to stack both destruction shards.

Just like with the Defense Range servo, Deadly Strikes will help combat frost orcs. Vicious Strikes can also be used, but the Deadly Strikes multiplier already works well on fissures. Therefore, it is recommended to save Vicious Strikes for another defense that poorly benefits from range multipliers.

Clean-Up Cannons

This build helps to deal with leaks, but the high damage that cannons deal to single targets also makes this build viable against Bosses as well.


  • Cheap - only 30 DU per cannon.
  • Very high DPS.
  • Can Stun enemies that tank multiple hits.


  • Completely useless against Vanguards and Geodes (unless you use a piercer servo).
  • Cannons can only damage one target at a time; can easily be overwhelmed by a massive horde.
  • Can be disabled by Kobolts or even destroyed if they do not have enough health. EMPs move way too fast for a single cannon or two to handle, and even a whole group is at risk of getting disabled.
  • Stuns aren't guaranteed to work (faster attack speed can increase the chance).


It is highly recommended to raise your cannonball tower to the speed cap. If you do not have a gilded Defense Rate shard, you can use a Defense Rate servo to reach the cap. The faster your cannon attacks, the more DPS it can deal, and the more likely it will stun its target.

Even a single cannon can chew through a Boss. The Anti-Miniboss servo can be used to improve this.

Berserker Orcs are the most common enemies that end up leaking through a crowd-control build due to their fast movement speed and immunity to all Slow debuffs. The Anti-Orc, Anti-Melee, and Anti-Chaos servos will all increase damage dealt to berserkers. If they become a problem, you can even stack these servos together to multiply the damage bonus against them!


Defense Rate is highly recommended to reach the speed cap. Mod slots are generally more valuable in this build, so it's better to use a shard slot to increase attack speed than to use a mod slot.

Cannon Stun is required to allow your cannons to stun enemies. The more you upgrade this shard, the more likely it is to successfully stun. Improving attack speed will also give this shard more attempts to stun its target.

Either Deadly Strikes or Destruction can be used for the last shard slot, depending on which suits you more. If you want to use this build against a group of enemies, the Heavy Cannonball shard gives a chance to fire a massive cannonball. Heavy cannonballs travel slowly, but can pierce through multiple targets.

Aerial Squirt Gun

The Sky Guard Tower already slows enemies it hits, but this build also utilizes drenching to further slow airborne enemies to a crawl... except they can't crawl.


  • Brings flyers almost to a complete stop. This can make it difficult for Kobolts to get in range of your sky guard or another tower to dive-bomb it.
  • Sky Guards can be modified to have an extremely long range, making the tower even harder to dive-bomb.


  • Costs 50 DU - considering the strength of this tower, it would normally be very cost-efficient, but it cannot attack ground units unless they are knocked up.
  • Can be disabled by Kobolts. The long range and double-stacking of slows can make this difficult, but they can still pull off their dive-bomb if they're tanky enough.
  • Completely useless against flyer lanes with the Unstoppable mutator.