REX is a unique hybrid half plant/half robot that uses its HP as a resource to cast long-range abilities. REX is one of the most challenging survivors to play in Risk of Rain 2 and is sometimes regarded as underpowered, yet that doesn’t make them any less of a fun challenge to play.
How To Unlock REX in Risk of Rain 2
REX – Power Plant
Rex is an incredibly difficult survivor to unlock in Risk of Rain. Power Plant requires you to pick up the Fuel Array from Stage 1 and bring it to the Abyssal Depths stage without dropping below 50% health. You cannot acquire the Fuel Array as Mul-T, Acrid, or Void Fiend due to the three of them spawning into the game outside of Drop Pods – where the Fuel Cell is acquired.
We recommend you pick up the Fuel Array after completing the first teleporter event and drop it for other Equipment items until you leave stages. The Fuel Array will end your run if you’re not careful, and it doesn’t help that you aren’t guaranteed to come to the Abyssal Depths when equipping it since there are three sets of fourth stages.
How REX’s Abilities Work in Risk of Rain 2
Passive – Natural Toxins
REX’s Passive is Natural Toxins which allows certain attacks to Weaken enemies hit for three seconds. Whenever an enemy is afflicted by Weaken, their movement speed and damage are also reduced, and they lose 30 armor.
Primary Skill – DIRECTIVE: Inject
Directive: Inject is REX’s first primary ability. It fires three syringes that deal 3×80% damage and has a proc coefficient of 0.5×3. The final syringe Weakens and heals for 60% of the damage dealt. Each shot from the burst can crit independently, and the shots fire in a horizontal fan, making long-range shots difficult.
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Drill is REX’s first secondary ability which launches a barrage of seed bullets into the sky, raining down a volley of seeds for 450% damage per second. This ability has a proc coefficient of 0.5 x16 with a cooldown of six seconds.
To unlock Drill requires your to complete the Bushwhacked challenge. Finishing this requires you to complete an entire teleporter event while under 50% health. REX has plenty of self-damaging abilities to keep themself under 50% health, but Shrines of Blood can help keep your HP down before starting the event. Using the Artifact of Glass or the Shaped Glass lunar item doesn’t count as being below 50% HP.
Seed Barrage is REX’s other secondary ability in Risk of Rain 2. It allows them to launch a mortar into the sky for 450% damage at the cost of 15% HP. This ability has no cooldown, with a proc coefficient of 1.0, and can be spammed so long as you have the HP to use the ability. Seed Barrage also has no falloff damage making it great for long-range engagements.
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Utility Skills that REX has in RoR2
Disperse is REX’s first Utility ability which fires a Sonic Boom that Weakens all nearby enemies hit. This ability has no proc coefficient, does no damage, and has a 5.5-second cooldown. The knockback from Disperse varies depending on the target’s size; larger enemies are pushed less than smaller foes. When Disperse is used in the air, this skill knocks REX back toward the camera.
Bramble Volley is REX’s second Utility which functions like Disperse. This ability launches a Sonic Boom that damages for 550% in exchange for 20% HP. Each enemy hit heals REX for 10% of their max HP.
To unlock Bramble Volley and use it in your Risk of Rain 2 REX build, you must complete the Dunked challenge. This challenge requires killing a Clay Dunestriker on the Abandoned Aqueduct stage by throwing it into a pit. Obtaining a Hardlight Afterburner makes this challenge more manageable, allowing you to spam Disperse more often.
Harvest is REX’s first ability which fires a bolt that deals 330% damage and injects an enemy. When that enemy dies, they drop several fruits that heal for 25% HP. This debuff lasts 10 seconds, giving you a limited window to kill your target. The number of fruits dropped scales with enemy HP ranging from 2-8 fruits.
To unlock Harvest, you must complete the Full of Life challenge. To finish this challenge, you must heal 1000 or more health in a single tick. The best way to achieve this amount of healing is to have Lepton Daisy or Foreign Fruit with a Rejuvenation Rack which will easily heal 100% of your max health.
Tangling Growth is REX’s second Special ability in RoR2, which fires a flower that roots targets for 200% damage in exchange for 25% of REX’s HP. REX is healed for roughly 1.5% of their Hp every second per snared target. Even if the entangled enemy is killed, REX will continue to be healed until the flower expires. Ultimately Tangling Growth is one of REX’s strongest abilities in their entire kit.
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The Best Risk of Rain 2 REX Build
REX feels very weak in the early game and requires several different items to function properly. There are some very specific must-haves items to include in your Risk of Rain 2 REX build. These include any items with Attack Speed and Movement Speed. Alongside these essential must-haves, Rex synergizes off of Leeching Seed due to the primary having multiple hits, Primordial Cube because Seed Barrage will hit more targets, and Tangling Growth will leech onto more enemies.
Your Risk of Rain 2 build for REX should include Razorwire due to the self-damage, Tougher Times because of the ability to negate self-damage, and any Legendary that Synergizes off of self-healing, and any item that heals.
Regarding Abilities, we recommend the basic setup that REX comes with on unlocking – Seed Barrage, Disperse, and Tangling Growth. The only thing that can honestly be disputed is the use of Bramble Volley, which can be really good for healing against enemies that get too close to REX. Regardless, REX’s DIRECTIVE abilities aren’t exactly the best since REX is so slow, and they barely heal them.
Tips & Tricks on How to Play REX in Risk of Rain 2
- Sprinting as REX puts the robot’s hitbox partially underground, making it harder to hit if trying to escape enemies.
- REX’s secondary ability, Seed Barrage, can be spammed as long as you have the health. This makes using it while Tangling Growth is active highly effective.
- Tougher Times can block self-damage from any of REX’s abilities. The same applies to Safer Spaces.
- Taking Power Elixir in your RoR2 REX build isn’t the best idea due to constantly fluctuating between different sums of health.
- Both of REX’s Utilities can be used in the opposite direction to knock yourself back and towards a location. These can also be used to knock enemies into hazards or endless pits.
- Even if enemies die or leave Tangling Growth, the healing still applies until the AOE expires.
Wrapping Up Our RoR2 REX Build and Gameplay Guide
Overall, REX is a tricky balancing act, requiring health detriments to make massive healing benefits. REX struggles against enemies early in the game, but they can really shine in the right circumstances. One of the biggest struggles for REX is accidentally pushing yourself over the threshold and dying because of expending too much HP. He is one of the more challenging characters in Risk of Rain 2 to master.
If you can overcome REX’s drawbacks, they are one of the highest sustaining survivors in all of Risk of Rain 2. We always love to hear from our readers. Please let us know what you think of our RoR2 REX build guide using the comments below.
For more insights into playing with other in-game characters, check out our guide on how to build Commando in Risk of Rain 2.