How to Get Solvent in Phantom Blade Zero (Weapon Upgrade Material)

Quick answer: Find a Solvent next to a lantern along the elevated trail inside the cave beyond the Great Waterfall in Weeping Creek Valley. Approach it and press E.

In Chapter 1, “AGAINST THE FLOW”, you arrive here after The Hunt’s second encounter at the Great Waterfall. Reaching the spot means going through the cave behind the falls and using the Hunter’s Chain Sickle to grapple once, so learn the route before heading out.

What Solvent does

Solvent is filed under “Weapon Upgrade Materials”. Its item card reads:

“A solvent compounded according to an age-old secret formula. One drop strips away rust, two make worn metal gleam anew, and three can etch fine patterns upon a blade.”

The effect line reads: “Universal material required to upgrade weapons to Lv. 10.” Every main Weapon upgrade calls for three things. You need the metal for that weapon type (Forged Metal for One-Handed, Twinned Metal for Dual-Wield), Solvent, and Remnant Dust.

Phantom Blade Zero SOLVENT item card under Weapon Upgrade Materials

Skip the Solvent and the upgrade simply won’t go through. On the Upgrade Equipment screen, taking Sanguine Twin from Lv. 1 to Lv. 2 lists Twinned Metal as owned 4 against a cost of 2, while Solvent shows owned 0 against a cost of 1 in red. The UPGRADE button, priced at 990 Remnant Dust, stays grey until that red line clears. The same screen previews what you would get at Lv. 2: Damage rises from 200 to 220 and Guard Break from 100 to 110.

Sanguine Twin upgrade screen in Phantom Blade Zero with 0 Solvent owned and the UPGRADE button greyed out

During your first encounter with the Forge at the Outpost, she tells you to bring a fine weapon of your choice, plus its matching forging metal and Solvent. The complete process appears in the guide to upgrading weapons.

Where to find Solvent behind the Great Waterfall

Start at the Great Waterfall bell. The first stretch of the cave route is laid out in full, with pictures, in the cave notes guide.

Follow the cave route behind the falls up to the grapple. Climb the ledge under the falls (Space, Scale), cross the wooden scaffold and the tunnel, climb the first X-scratched wall by the brazier, and pass the red-candle shrine. Then grapple up the cliff beside the shrine with the Hunter’s Chain Sickle by pressing Left Ctrl on the anchor point.

Starting above the grapple ledge, use W + Space to scale the second wall marked with an X. Continue to its rocky summit, where a gully and broken rock lie ahead. The drops are fatal, so neither leap over the gully nor step off the wall’s edge.

Soul on top of the second scratched wall in the cave behind the Great Waterfall in Phantom Blade Zero

From the top of the second wall, look for an orange glow and walk along the rock toward it. A level stone path carries on without a gap toward an orange-lit rock face with a small lantern at its foot.

Stone path leading to the lantern and orange-lit rock where Solvent lies in Phantom Blade Zero

Continue along the trail until you reach the lantern post. Look for a small white glint on the ground, just to its right and in front of the illuminated rock.

Solvent glint on the ground beside the lantern post in Phantom Blade Zero

Once beside the glint, press E when the interaction prompt appears. The SOLVENT item card confirms you’ve collected it; press Space to dismiss the card.

E prompt to pick up Solvent beside the lantern in Phantom Blade Zero

Solvent cost per weapon upgrade

These are the Solvent costs shown on the upgrade screen:

Upgrade	Metal	Solvent	Remnant Dust
Jagged Steel Lv. 1 to Lv. 2	2 Forged Metal	1	1,080
Jagged Steel Lv. 2 to Lv. 3	4 Forged Metal	2	1,620
Sanguine Twin Lv. 1 to Lv. 2	2 Twinned Metal	1	990
Dread Axe Lv. 1 to Lv. 2	1 Darkfire Charcoal	None	640

Phantom Edges run on different materials, which is why the Dread Axe asks for Darkfire Charcoal instead of Solvent. If you change your mind about a weapon, reverting it to Lv. 1 refunds the Solvent together with the metal and Remnant Dust you spent.

Concentrated Solvent and Universal Solvent for higher levels

Solvent only takes a weapon as far as Lv. 10. Past that point, two stronger versions take over.

Material	Upgrade range
Solvent	Up to Lv. 10
Concentrated Solvent	Lv. 10-20
Universal Solvent	Lv. 20 to max level

Concentrated Solvent’s card reads: “Several measures of solvent are simmered over a gentle flame to produce this small vessel of concentrated solution. Fiercely corrosive, it can eat through stubborn iron as though it were clay and hone a dull blade to a keen edge. A steady hand and utmost caution are essential when using it.” Its effect line is “Universal material required to upgrade weapons from Lv. 10-20.”

Universal Solvent’s card reads: “All things in this world are bound by shared principles and a subtle harmony. Thus, craftsmen versed in arcane arts devised this solvent to fuse disparate materials into one, lending an even keener edge to weapons tempered through a hundred trials.” Its effect line is “Universal material required to upgrade weapons from Lv. 20 to max level.”