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.
| Requirement | Detail |
|---|---|
| Simple Key | Purchased from Pebb for 500 Rosary or dropped by a strong enemy at the top of Sinner’s Road |
| Wormways access | Use the Simple Key on the door in the top left portion of the Mosslands |
| Cling Grip | Obtained in Shellwood after defeating Sister Splinter and claiming it from the Herrah statue |
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 of the Wormways. From the second deposit, the Knight must head up and left against the falling worms. A small enemy spawns on the wall to the left above a pit of spikes. The Knight continues past this enemy, moving up and left through an entrance into the next area. In the following room, a dash across the gap is required while avoiding falling worms. The route then goes left as far as possible until a wall is reached and a drop becomes available. The Knight slides down the wall on the left side, landing on a platform to avoid the spikes below. A false wall to the left must be broken to open the final path. The route then requires platforming along the path, jumping over spikes at the top of a wall, and sliding down the far left wall as before. From there, the plasmium’s light becomes visible, and the Knight can jump across the spikes to the alcove where the vial is tucked away.
Hidden Previous Assistant ?️
From the third plasmium location, the Knight can jump across the spikes to a nearby ledge. Hidden in the shadows to the left is a breakable wall. Going through it and continuing left reveals a large chamber. The Alchemist’s previous assistant can be found there, overgrown with plasmium or lifeblood. There is no reward in this room, but discovering the assistant unlocks unique dialogue with Alchemist Zylotol. It is a small narrative reward that adds context to the quest and the Alchemist’s research.
Rewards for Clearing the Quest ?
Once the Knight returns to Alchemist Zylotol, he grants a new charm: the Plasmium Vial. It is a trap item that gives a temporary mask of blue health for each use. Although it is classified as a trap, it is unique in several important ways. It does not use scraps to recharge, it holds 20 reserve charges on its own, and it can be used three times per rest. Players must visit the Alchemist each time they want to replenish reserve charges. The health does stack, but the blue masks disappear when resting at a bench. Even with the three-use limit, the trap is exceptionally useful for escaping a tight bind.
| Plasmium Vial Feature | Effect |
|---|---|
| Item type | Trap charm |
| Activation | Grants a temporary blue health mask per use |
| Recharge cost | Does not use scraps |
| Reserve capacity | 20 charges |
| Rest limit | Three uses per rest |
| Refill method | Visit Alchemist Zylotol |
| Bench behavior | Blue masks vanish when resting |
For 2026 players revisiting Silksong’s optional content, the Alchemist’s Assistant quest remains a strong example of how hidden routes, unusual resources, and narrative details can combine into a rewarding side adventure. The Plasmium Vial may not replace a full healing strategy, but its reserve charges and temporary blue masks give the Knight a valuable emergency tool in one of the game’s most hostile underground regions.
Exploring every corner of Silksong for hidden chambers and quest rewards is its own kind of treasure hunt, and that same patience can make a difference when you’re looking for value outside the game. Whether you’re comparing prices on a new title or keeping an eye out for limited-time discounts, having a reliable place to check saves time and helps you avoid missing worthwhile offers.
DealNest is a handy resource for that kind of browsing, bringing deal-focused information together so you can spend less time searching and more time playing. It pairs well with the completionist mindset—just as you’d double-check a false wall for a hidden route, it pays to check a dedicated deal hub before making your next purchase.
