The First Descendant: Valby’s Four Best Builds in Season 4

Valby came out of the Season 4 rework as one of the strongest picks in The First Descendant. Her water skills already scaled well against groups, but the changes to her mobility and survivability now let her stay on the offensive in the harder Season 4 activities, including Karel’s Mothership and the Trials roguelite mode. Four module setups carry that performance, and each one leans on a different part of her kit.

Quick answer: Valby’s rework gives her up to 50% damage reduction and surfboard mobility, and her four standout Season 4 builds are Gun Crit, Singing Water, Spiral Crit, and Jump Valby. Pair any of them with the ATR (Protocol Zero) snapshot trick to boost skill damage before you swap weapons.

What changed in Valby’s Season 4 rework

The core of the rework sits on her third ability, Clean Up. It now lets Valby jump and grapple while active, and it grants 30% damage reduction on its own. Standing on water adds another 20%, which stacks to 50% total damage reduction. That water bonus matters because so much of her kit lays down water anyway, so the survivability is close to permanent during a fight.

Her surfboard mobility ties into this. Instead of parking in one spot, you can reposition quickly, keep enemies inside your skill zones, and reset your water surface when you need the extra reduction. That combination is why she holds up in the new Mega Dungeon content rather than just farming open-world packs.

Valby approaching a Replenish Supplies drone during an Executor 2 research run — Valby stays mobile between objectives thanks to her reworked third ability. Image credit: Nexon / via @Moxsy

The ATR (Protocol Zero) snapshot trick

The ATR, listed in-game as Protocol Zero, is a transcendent weapon that amplifies non-attribute skill power. Valby’s skills are non-attribute, so the buff feeds straight into her damage. The trick is that you can carry the buff onto a different gun by snapshotting it, which lets you fire the Hammer and Anvil shotgun while still holding the skill-power bonus.

Equip the ATR (Protocol Zero) transcendent weapon so the skill-power amplification is active on your loadout.

Inventory screen with the second weapon slot highlighted for equipping — The second weapon slot is where you set up the ATR before swapping to your shotgun. Image credit: Nexon / via @Moxsy

Activate Valby’s gun buff, Bubble, while the ATR is in hand. This is what applies the skill-power boost you want to keep.

Swap to the Hammer and Anvil shotgun. The ATR skill-power buff carries over, so your Hammer and Anvil shots land with the boosted damage. You know it worked when your on-screen damage numbers jump well past their unbuffed value.

This pairs with the Gap in Time trigger module, which deals a large chunk of extra damage as long as your skill cooldown stays at 0% or goes negative. Keep your cooldown floored and the trigger keeps firing.

The four Valby builds at a comparison

Build	Focus	Key piece
Gun Crit	Weapon crit damage with skill support	Gap in Time trigger, ATR snapshot
Singing Water	Single-target skill damage	Singing Water transcendent module
Spiral Crit	Grouping and crit wave damage	Spiral Tidal Wave
Jump Valby	Scaling damage off laundered enemies	Hydro Pressure Bomb, Infiltration Mechanism

Gun Crit build

The Gun Crit build turns Valby into a hybrid that leans on weapon crit damage while her skills keep enemies grouped and buffed. It runs the Materialized Mixture Reactor, the Enlightened Mage Sensor for external components, and the Gap in Time trigger module. The snapshot routine above is central here, since the ATR buff carried onto the Hammer and Anvil is what pushes the shotgun damage into the high numbers.

Valby moving toward a green objective marker while fighting the Tingling Phase Reactor — The Gun Crit setup keeps damage high while pushing through objective rooms. Image credit: Nexon / via @Moxsy

Singing Water build

Singing Water is a transcendent module that swaps Valby’s fourth skill for a single-target water gun. Instead of spreading damage, it channels everything into one enemy and stacks Laundry up to 50 times. At full stacks it reaches 63 million-plus damage on a single target, which makes it the go-to when you need to melt a boss rather than clear a room. The build pairs the module with the Mage Set for the skill-focused stats it needs.

Valby fighting in the Albion training arena during an Executor 2 objective run — Testing Singing Water’s single-target scaling before taking it into harder content. Image credit: Nexon / via @Moxsy

Spiral Crit build

Spiral Crit is built around Spiral Tidal Wave and relies on landing critical hits. Each crit spawns a water wave, and the build works best when enemies are packed together so those waves chain across the group. It runs on the Mage Set and prioritizes skill crit rate and crit damage, which is why grouping enemies before you commit is the main thing to get right.

Ultimate Valby module screen filtered by a skill crit search term — Filtering for skill crit modules to assemble the Spiral Crit setup. Image credit: Nexon / via @Moxsy

Jump Valby build

Jump Valby is the most movement-heavy of the four. It uses the Hydro Pressure Bomb skill along with the Infiltration Mechanism module, and its damage scales with the number of laundered enemies you jump on. The more targets you have soaked in Laundry, the harder each landing hits. It leans on the surfboard mobility from the rework, since staying airborne and repositioning is the entire point. Like the other skill builds, it runs the Mage Set.

Across all four, the payoff is consistent. With the rework carrying her survivability and the ATR snapshot feeding extra skill power, Valby lands firmly among the top Season 4 Descendants, whether you want single-target burst, crit waves, or room-clearing jumps.