If you’ve spent even a few hours running void missions or farming boss drops in The First Descendant, you’ve probably stumbled across reactors – the weird, glowing core items that slot into your descendant’s loadout to boost their core skill power and passive stats. A ton of new players reach out every week asking can you level up reactors in the first descendant, and the short answer is a little more complicated than a straight yes or no. Reactors work differently than standard weapons or descendant level upgrades, so if you’re wasting resources trying to power up a low-tier drop, you could be setting your build progress back by hours. This guide breaks down exactly how reactor progression works, which upgrades are worth chasing, and how to get the strongest possible version of your favorite reactor for endgame runs.
Can You Level Up Reactors in The First Descendant? Core Mechanics Explained
First, let’s clear up the most common misconception: you won’t earn XP for your equipped reactor while running missions, so they don’t level up passively the same way your descendant or weapon does. That doesn’t mean you’re stuck with the stats of the first reactor you pick up, though. Reactors have two separate progression paths that let you boost their power significantly, even if you’re using a mid-tier drop you got early in the game. The first is stat enhancement, where you use reactor boosters and credit to raise the value of their fixed core stats, like skill cooldown reduction, max energy, or passive damage resistance. The second is rerolling optional substats, where you can swap out useless perks (like ammo capacity for a skill-focused build) for ones that fit your playstyle.
You might have noticed that some reactors have a number next to their name when you loot them, like “Frost Reactor Lv.30”. That number is the minimum descendant level required to equip the reactor, not a level you can raise by using it. The only way to get a higher level reactor is to loot one from higher difficulty missions, but you can still upgrade a lower level reactor’s stats to be viable for content 10 levels above its required equip level, as long as you invest the right materials. I’ve seen a lot of new players scrap rare reactors because they think they can’t make them stronger, but that’s almost always a mistake – even a B-tier reactor can be upgraded to outperform a base S-tier drop if you build it right.
How to Boost Your Reactor’s Power Without Traditional Leveling
Upgrading your reactor’s power is pretty straightforward once you know what materials to farm, and you don’t have to wait until endgame to start making improvements. I usually start tweaking my reactor as soon as I hit level 20 on my main descendant, since that’s when you start running missions that drop enough enhancement materials to make the grind worth it. The step-by-step process to maximize your reactor’s power looks like this:
- First, unlock all enhancement slots for your reactor by using 5 common reactor boosters per slot. Most common reactors start with 2 locked slots, and unlocking all 4 gives you 2 extra stat boosts you can raise to match your core perks.
- Next, enhance your core fixed stats first before touching substats. Prioritize stats that directly boost your descendant’s signature skill, like skill damage increase for DPS descendants or support skill efficiency for healer or tank builds.
- Once your core stats are maxed, use substat reroll tokens to swap useless perks for ones that fit your build. You can reroll each substat up to 5 times, so stop once you get a perk that gives at least a 7% boost to your core build stat.
- Finally, fuse duplicate reactors of the same type to unlock hidden passive perks. Fusing 3 duplicates of the same reactor gives you a permanent 10% boost to all reactor stats, which is a bigger power jump than most endgame weapon upgrades.
I made the mistake of rerolling substats first on my first main reactor, and I wasted almost 20 reroll tokens on a reactor I hadn’t fully enhanced yet, so don’t make that same call. You’ll get far more value if you max out core stats first, then tweak substats to fill gaps in your build. You can farm reactor boosters from daily challenge missions, which take 10 to 15 minutes each to complete and give you 10 to 15 common boosters per run. Reroll tokens drop from weekly void missions, so I usually save all my tokens for the end of the week once I’ve settled on a reactor I want to keep for a few weeks.
Are Higher Rarity Reactors Worth Replacing Your Upgraded One?
Once you start running S-tier void intercept missions, you’ll start picking up legendary and ultimate rarity reactors, and you might be tempted to swap out your fully upgraded epic reactor immediately for the higher rarity drop. That’s usually not the right call, especially if you’ve already invested a lot of materials into your current reactor. A fully upgraded epic reactor will outperform a base legendary reactor by at least 15% for the first 10 hours you own the legendary drop, since you’ll have to re-upgrade all its stats from scratch. So when is it worth swapping? I only swap to a higher rarity reactor if it has a core fixed stat that’s impossible to get on my current reactor, like a 20% signature skill damage boost that my epic reactor doesn’t have.
You also want to make sure you have enough spare materials saved up to max out the new reactor’s core stats in one go, so you don’t lose a bunch of power mid-grind. For example, my main is a Viessa build, and I stuck with a fully upgraded epic frost reactor for almost 3 weeks after I got my first legendary frost reactor, because I didn’t have enough boosters saved up to max the legendary one right away. I only swapped once I had enough materials to get the legendary’s core stats to 90% of my epic’s level, so I didn’t have to struggle through harder missions with a weaker build. If you’re playing in a regular group, you can even ask your squad to run lower difficulty missions with you to farm the boosters you need to upgrade your new reactor faster, so you don’t have to grind alone.
Top Tips to Optimize Your Reactor for Endgame Content
Even if you’ve fully upgraded your reactor’s stats, there are a few small tweaks you can make to get even more power out of it, especially for endgame content like void chases and world boss raids. First, make sure your reactor’s element matches your descendant’s signature skill element. If you’re running a fire-focused descendant like Burnside, a fire reactor will give you an extra 25% skill damage boost that you won’t get from a generic non-elemental reactor, even if the non-elemental one has higher base stats. Don’t sleep on hidden synergy perks that activate when you pair a specific reactor with a specific descendant. For example, pairing the Glacier Core reactor with Viessa gives you a permanent 15% freeze duration boost, which is a game-changer for crowd control in group raids.
Another tip I swear by is to keep at least two fully upgraded reactors on hand for every descendant you play regularly. One should be built for single-target damage for boss fights, and the other should be built for area-of-effect damage for clearing waves of mobs in void missions. Switching between them takes 10 seconds in the loadout menu, and it makes every run way smoother. You also want to avoid wasting enhancement materials on common or uncommon rarity reactors. These drop so frequently that you’ll find a rare or epic version of the same reactor within a few hours of play, so any materials you put into lower rarity reactors are basically thrown away. If you have extra low rarity reactors sitting in your inventory, you can dismantle them for small amounts of reactor boosters and credits, which is far more useful than trying to upgrade them.
At the end of the day, the question of can you level up reactors in the first descendant comes down to how you define leveling. You won’t raise their base level via XP like you do other gear, but you can boost their stats significantly to keep up with even the hardest endgame content, as long as you farm the right materials and prioritize upgrades that fit your build. Don’t scrap a perfectly good mid-tier reactor just because you think you can’t make it stronger, and don’t swap to a higher rarity drop until you have enough materials to upgrade it enough to match your current build’s power. With a little bit of grind and smart upgrade choices, you’ll have a reactor that carries you through every mission in the game without any issues.