In 2026, Hollow Knight: Silksong’s Wormways remains a dangerous detour for even seasoned players, but the Alchemist’s Assistant quest gives the brave a chance to turn a strange blue substance into a lifesaving advantage. The optional assignment from Alchemist Zylotol sends the Knight through cramped tunnels, falling worms, spike pits, and false walls in search of three plasmium deposits. The payoff is the Plasmium Vial, a trap item that grants temporary blue health and can pull a run back from the brink. The quest is not especially long, yet its hidden route and unusual reward make it one of the Wormways’ most memorable secrets.

Quest Start and Requirements 🗝️

The Alchemist’s Assistant quest begins only after the Knight has unlocked the Wormways. Access requires the Simple Key, which can be obtained in one of two ways at this stage: it can be bought from Pebb for 500 Rosary, or it can drop from a strong enemy at the top of Sinner’s Road. The first option is the more likely path for most adventurers, but either method works. Once the key is in hand, it must be used on the Wormways’ door in the top left portion of the Mosslands.

Reaching Alchemist Zylotol 🧪

Inside the Wormways, Alchemist Zylotol is located at the topmost portion of the map in the center. His chamber sits in an opening above a long wall, which means Cling Grip is required to reach him. Players who do not already have Cling Grip must venture into Shellwood, defeat Sister Splinter, and claim the ability from the Herrah statue at the top of the area. With wall-climbing available, the Knight can mount the walls and speak with Zylotol.

After accepting the quest to gather plasmium, players should not leave immediately. The special equipment from Zylotol must be equipped first. The Knight should sit on the bench to the Alchemist’s left and equip the Needle Phial to the trap slot. This step is easy to overlook, but it is essential for harvesting the blue deposits scattered through the area.

Plasmium Harvesting Basics 💙

Each plasmium deposit appears as a bright blue liquid-filled flower, making it difficult to miss once it comes into view. When the Knight reaches a deposit, the trap button must be held down until the phial is charged. Releasing the button then injects and absorbs the plasmium contents. The process is simple, but the journey between deposits is where the Wormways tests patience and precision.

First Plasmium Location

The first plasmium is the closest and most misleading of the group. Although the Alchemist’s instructions point toward the bowels of the Wormways, this deposit is actually near the Alchemist. After leaving Zylotol’s room and descending into the main Wormways chamber, the route takes a slight left and drops past falling worms. The Knight then continues left, climbs a small hill, and floats down toward a blue light and an alcove on the right. The plasmium sits nestled within that alcove, ready for harvesting.

Second Plasmium Location

From the Alchemist’s room, the Knight must head for the bottom of the Wormways. The path goes down two rooms from Zylotol, into a dark portion of the map where visibility is limited. From the entrance into this area, players should stay right and navigate the corridors downward. When moss begins to appear, the route shifts to the right. As with the first deposit, the Knight should head toward the blue light as soon as it appears, which leads directly to the second plasmium location.

Third Plasmium Location

The third plasmium demands a more careful route toward the bottom left corner o
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