S-TIER | BUILD MERCENAIRE FLAMEBLAST OIL GRENADE (@ds lily) | SAISON 5

Build Video

Build Overview

This mercenary build revolves around Flameblast and a simple idea that is deceptively brutal in practice: you channel Flameblast to lay down a burning ground, then push it around indefinitely with Oil Grenade. Once the fire carpet is lit, maps clear themselves with a single button. Its creator, ds lily, took it on a « 1 divine » run and killed every boss with gear picked up during the campaign, 200% delirium included.

The Gemling Legionnaire ascendancy isn’t a cosmetic detail: it’s the engine driving the whole build. Gem quality becomes the main multiplier, and Flameblast grants more ailment magnitude at every channeling stage. At ten stages and 26% quality, that’s 520% extra magnitude on the burning ground. Oil Grenade damage, on the other hand, counts for nothing: the grenade only exists to push the burning ground around.

The real standout, something other current guides tend to skip over, comes down to one word: snapshotting. The burning ground locks in its damage the instant it’s created. That means you can gear into something absurd for a single cast, then swap it right back out without losing anything. The dedicated section below breaks down the technique, because it’s the difference between a solid build and one that erases the Arbiter in two seconds.

Strengths / Weaknesses

Skill Gem Setup by Step

This build offers 5 progression steps from leveling through to the final build. Select a step to see the matching gem setup.

~Lvl 25 ~Lvl 47 ~Lvl 51 Lvl 52 Flameblast / Oil Nade Transition ~Lvl 72

~Lvl 25

8 skills • 17 gemmes

Grenade explosiveExplosive Grenade

Grenade assourdissanteFlash Grenade

Grenade suffocanteGas Grenade

Héraut de la cendreHerald of Ash

Danseur du ventWind Dancer

Bombe de givreFrost Bomb

BondissementPounce

Rugissement féroceFerocious Roar

~Lvl 47

8 skills • 20 gemmes

Grenade explosiveExplosive Grenade

Grenade assourdissanteFlash Grenade

Grenade suffocanteGas Grenade

Grenade à huileOil Grenade

Héraut de la cendreHerald of Ash

Danseur du ventWind Dancer

Rugissement féroceFerocious Roar

BondissementPounce

~Lvl 51

0 skills • 0 gemmes

Lvl 52 Flameblast / Oil Nade Transition

7 skills • 21 gemmes

ConflagrationFlameblast

Grenade à huileOil Grenade

Danseur du ventWind Dancer

TornadeTornado

Sensibilité aux élémentsElemental Weakness

Armure arctiqueArctic Armour

Étendard de défiDefiance Banner

~Lvl 72

1 skills • 6 gemmes

ConflagrationFlameblast

Recommended Equipment

The hierarchy is clear: the staff and the amulet carry the damage, everything else carries survival. Anything that doesn’t fall into these two slots can stay mediocre for a very long time without holding back your progress.

One note before the list: the interactive grid further down faithfully reproduces ds lily’s planner, which he himself describes as unfinished in his video’s description. You’ll therefore only see magic and rare pieces there, without the unique items listed below. That is precisely the point of the build, capable of running on ordinary gear. The pieces below are the targets described in the video, to aim for as you level up.

• Staff: the centerpiece. You’re looking for gem levels in bulk, spell damage, and fire damage. The Searing Touch can be equipped from level 16 and costs next to nothing at the start of the league: it’s the build’s best-value purchase.
• Amulet: Fireflower and its stack of fire levels are used for the snapshot. Once the ground is laid, you switch to Xophs Blood, whose exposure stacks on top of damage that’s already locked in.
• Crossbow: almost beside the point, since Oil Grenade‘s damage doesn’t count. A base with extra grenade projectiles and levels widens the area of effect; strength or dexterity for the requirements, and strength runes for a bit of life.
• Body armour and defensive pieces: hybrid evasion/armour bases hold up better than pure armour once ward is added. A rare with very high life gets the job done early on, Morior Invictus takes over later.
• Rings and gloves: the only rule that matters: zero flat fire damage. Doedres Damning earns its spot if you want an extra curse.
• Spirit gems: Arctic Armour benefits enormously from quality (26% armour per tier, up to six), Wind Dancer brings evasion and pushes monsters back. With enough spirit, Blasphemy and Temporal Chains slow packs by more than half; otherwise, Defiance Banner gives armour, evasion, and a bit of movement speed.

Gameplay Tips

• The rotation comes down to two moves: channel Flameblast on the first pack, then only use Oil Grenade until the end of the map.
• Snapshot before every boss: damage amulet equipped, ground laid down, amulet swapped back. Thirty seconds of juggling for a multiplier that costs nothing.
• Keep Tornado on hand: it’s the only way to lift the burning ground to hit flying monsters, which the grenade ignores entirely.
• If you can’t replace a flat fire piece, slot Elemental Focus onto every skill that deals that damage type, otherwise their ignite overwrites yours.
• Don’t lose your ground: getting it back means re-channeling on an enemy, and a botched attempt chains straight into a long cooldown.
• On bosses with Blasphemy, stay far enough away to apply your elemental weakness, or find an extra curse. Failing that, drop the aura for the fight.

Snapshotting: the mechanic other guides overlook

The burning ground from Flameblast is a world object, not an effect tied to your character. Once created, it keeps the damage calculated the moment it appeared and never recalculates it again. So you can pull the stat that produced it: the sheet of flame keeps hitting as if it were still there.

In practice, the maneuver comes down to three steps. You equip a Fireflower amulet loaded with fire levels at the entrance of a map or in front of a boss. You channel Flameblast, spread it with Oil Grenade until you get the ground you want. You then swap the amulet for Xophs Blood, whose exposure gets added on top of damage that’s already locked in. The same principle works with other pieces if you have the patience to keep swapping, but the amulet alone captures most of the gain.

ds lily makes a point worth repeating: the end-game guides written about this build never mention it, and the videos he himself recommends for continuing your progression (this one and that one) don’t put it to use either. So you start out with a free multiplier that most players of this archetype leave on the table.

Rating the Mercenary Flameblast build: damage, defence, clear

The author rates his own build without going easy on it, and the breakdown says it all. Damage lands a flat 10 out of 10. Defence gets 6 out of 10: nowhere near the 20,000 energy shield points of a dedicated build, but well above the average life-based build. Clear speed caps out at 5 out of 10, locked in by the grenade’s area of effect.

And then there’s the rating no other build gets: 0 out of 10 for framerate. This isn’t a creator’s joke. On an RTX 4080 Super paired with a 7800X3D, ds lily plays on low settings just to avoid getting stuck at 30 frames per second. Against the Arbiter, your own fire effects blanket the screen over its own, to the point where you can no longer make out its attacks. The fight is over in two seconds, which makes the problem bearable, but if your machine is only just up to it, factor that in before committing to the league with this archetype.

Where the damage comes from

The core multiplier is gem quality, hence the choice of Gemling Legionnaire. Flameblast grants more ailment magnitude per channelling stage: ten stages at 26% quality produce 520% extra ignite magnitude. No piece of gear in the game offers a comparable figure for such a low investment. Everything else in this mercenary Flameblast build is built around that single figure.

Your staff rounds out the equation with its gem levels, spell damage, and fire damage. The Searing Touch, equippable from level 16, fills that role for a handful of exalted early in the league.

One corollary is surprising at first glance: Oil Grenade‘s damage counts for nothing. The grenade is a positioning tool, tasked with spreading the burning ground, and your Flameblast damage is attached to it, not the grenade’s own. Your crossbow can therefore stay lukewarm for dozens of levels without the build’s power shifting an inch.

Where the defence comes from

The life pool exceeds that of other life-based builds, thanks to stacking Virtuous Barrier, Xophs Blood, and later Morior Invictus. A very-high-life rare holds up perfectly well in the meantime. Hybrid evasion/armour bases hold up better than pure armour once ward is added, which shapes gear hunting from the campaign onward.

Spirit gems do the rest, and quality serves them just as much as the offensive skills: Arctic Armour gives 26% armour per stage, more still with higher quality, over six stages. Wind Dancer benefits less from quality but brings evasion and knockback. Blasphemy linked with Temporal Chains slows base-tier monsters by more than half, at the cost of a trade-off on bosses.

The Mercenary’s passive tree, finally, is packed with hybrid armour/evasion nodes that stack cleanly with gear and auras. The stun thresholds scattered in that same area are picked up almost along the way, and it’s one of the class’s best investment-to-survival ratios: staying alive here costs a few passive points, where other archetypes have to dedicate entire items to it. That is what gives this mercenary Flameblast build a survival margin its damage alone would never suggest.

Skill Tree