Voltaic Amber is the Tarstone that puts Lightning on your sidearm in Mortal Shell 2, and it sits behind an optional mini-boss most players walk straight past. The drop comes from the Starved Harridan in the Vestige of Infinity, a snowy ruin tucked south of Castigator’s Keep that never appears on the critical path.
Quick answer: Kill the Starved Harridan in the Vestige of Infinity, reached by taking the elevator inside Castigator’s Keep. She drops Voltaic Amber and Voltaic Essence together.
What Voltaic Amber does
Voltaic Amber is an Infusions-type Tarstone that equips to the sidearm slot. Activating it spends 20 Resolve and coats your shots in Lightning, which deals damage over time. Stack enough applications on a single target and the buildup releases a shockwave that spreads damage to anything nearby.
The duration scales with the Tarstone’s level, so the early version burns through fast and needs recasting mid-fight.
| Level | Effect |
|---|---|
| 1 | Consume 20 Resolve to infuse your sidearm with Lightning |
| 2 | Infusion lasts for 4 shots |
| 3 | Infusion lasts for 8 shots |
| 4 | Infusion is permanent |
At the final level the infusion stays live as long as the Tarstone is slotted, so there is no Resolve cost or recast to manage. That is the point where Voltaic Amber becomes a set-and-forget part of a build rather than a mid-combat button press.
Note: Voltaic Amber is not Voltaic Crown. Crown is the Lightning infusion for your primary weapon, costs 30 Resolve, and drops from Vrago, Solikar Champion in the Abandoned Shrine. Amber is sidearms only.
Which sidearms accept the infusion
Two sidearms take Voltaic Amber, and both reward the pairing differently. The Salvaged Trebuchaxe fires slow, heavy shots, which suits the limited shot counts at lower Tarstone levels. The Triarch Repeater puts out volume, which builds Lightning stacks toward the shockwave faster.
| Sidearm | Why it works |
|---|---|
| Salvaged Trebuchaxe | High damage per shot, so each limited charge lands hard |
| Triarch Repeater | Faster fire rate builds Lightning stacks toward the shockwave |
Route to the Vestige of Infinity from Castigator’s Keep
The most direct approach starts from the Outskirts of Mammon beacon and runs south. The whole trip is short once you know the elevator exists, since the lift inside the Keep is the only thing connecting the fortress to the snowy region below.
If the arena is empty when you arrive
The encounter is gated by your approach. Entering from the top, via the northern portal route, leaves the arena sitting empty — the room is the same space either way, but nothing spawns. Coming in from the west side of The Silent Steps triggers her reliably, as does the elevator route from Castigator’s Keep.
If you walk into a quiet arena, leave the area and re-enter from the western path. There is no other switch or prerequisite involved.
Beating the Starved Harridan
She closes distance fast and punishes long melee trades. Her ranged projectiles are the manageable threat — the broken stone pillars scattered around the arena absorb them, so use cover instead of dodging every volley.
The screech is the attack that ends runs. Back well outside its range the moment she winds up rather than trying to tank it. Otherwise, stay at medium distance, let her long attack strings finish, land two or three hits, and disengage before the next sequence starts. Keep stamina in reserve for that retreat.
The arena sits beside the lift shaft, so knocking her into the drop is possible. Treat it as a shortcut, not the intended solution. Builds carrying duplicate or phantom summons trivialize the fight, since the clones hold aggro while you attack — keeping Resolve topped up lets you re-summon them.
How to confirm you got it
Two rewards land at once. Voltaic Amber appears under Tarstones, ready to slot into a compatible sidearm. Voltaic Essence goes into your key items and has no equip button, which trips up plenty of players — that is normal.
| Drop | What it does |
|---|---|
| Voltaic Amber | Equippable Tarstone; Lightning infusion for sidearms |
| Voltaic Essence | Permanent key item; works passively and is never consumed |
Voltaic Essence needs no activation. Simply holding it opens the sealed door on the southern edge of the arena, which leads on toward the Gate of Infinity beacon. It also powers the Lightning Spires scattered through the Vestige of Infinity and The Silent Steps.
Warning: A Lightning Spire unpetrifies the statues around it, and those enemies come back hostile. Heal and check how many figures surround a spire before walking up to one, because there is no prompt and no way to cancel the trigger.
Upgrading Voltaic Amber at the Tarforge
Levelling the Tarstone requires the Etching Needle, a quest item you hand to Franz to expand the Tarforge options in the Marrow Keep. The needle sits in a bone chest just before the Magdalena, the Lady of the Woods boss fight. When you spot Ruk past the bridge, drop through the opening and turn right before the tunnel to reach the small alcove holding it.
After that, keep Voltaic Amber equipped and kill enemies to fill its experience bar. Once the bar is full, return to Franz and pay Coin for each level. Pushing it to the permanent infusion is the upgrade that actually changes how the sidearm plays, since you stop budgeting Resolve around reapplying Lightning mid-fight.
