Mina the Hollower‘s Radiant Manor hides one of the more easily missed upgrades in the game. The Afterstrike Upgrade is locked behind a secret courtyard area that cannot be reached through normal exploration. To access it, you’ll need to uncover a hidden route from Station Underside, invest several Vials, defeat a mini-boss, and finally unlock the Red Chest waiting at the end.
| Requirement | Details |
|---|---|
| Upgrade | Afterstrike |
| Region | Radiant Manor |
| Access Point | Station Underside |
| Required Sidearm | Drill Diver |
| Vials Needed for Tunnel | 4 |
| Vials Needed for Chest | 5 |
| Total Vials Required | 9 |
| Boss Required | Yes |
| Reward | Afterstrike Upgrade |
Where the secret chest is located
The Red Chest sits inside a hidden courtyard connected to Radiant Manor. When you first see the chest, it appears inaccessible behind a blocked section of the manor grounds. The only way to reach it is through a secret underground path accessed from the Station Underside area.

The route is completely optional, making it easy to overlook during a normal playthrough.
Requirements before attempting the route
Before heading for the chest, make sure you have the following:
| Requirement | Purpose |
|---|---|
| Drill Diver Sidearm | Opens the hidden tunnel |
| 9 Vials | 4 for the entrance and 5 for the chest |
| Combat-ready equipment | Needed for the courtyard guardian fight |
Without the Drill Diver, you won’t be able to access the hidden passage leading to the courtyard.
How to get the Afterstrike upgrade by unlocking Red Chest
Step 1: Travel to Station Underside
Begin by heading to Station Underside. This underground area contains the hidden access point required to reach the courtyard beneath Radiant Manor.

Look for the section where the Drill Diver can interact with the terrain to reveal a secret path.
Once you locate the secret entrance, use the Drill Diver Sidearm to access the underground tunnel.
A mechanism here requires 4 Vials to activate. After paying the cost, the passage opens and allows you to continue toward the hidden courtyard area.

This is the first major resource gate preventing early access.
Step 3: Burrow through the secret passage
Continue through the newly opened route.

Use the Drill Diver to move through the tunnel and emerge inside the previously inaccessible courtyard connected to Radiant Manor.
At this point, you’ll finally be standing in the area where the Red Chest is located.
Step 4: Defeating the courtyard guardian
Before the chest can be claimed, you’ll need to defeat a lone armored guardian protecting the area.

The encounter is relatively straightforward compared to many major bosses, but the confined arena means you’ll still need to dodge carefully and avoid becoming trapped by the enemy’s attacks.
Once the guardian falls, the chest becomes available for unlocking.
Step 5: Spend 5 more Vials
After defeating the guardian, approach the mechanism beneath the Red Chest.

The chest remains sealed until you provide 5 additional Vials.
Insert the Vials into the box and the lock will disengage, granting access to the reward inside.
Step 6: Collect the Afterstrike upgrade
Open the Red Chest to obtain Afterstrike.

The upgrade description reads:
Hold Attack for an extra pulse of damage. Keep holding to flail.
This enhancement improves your offensive capabilities by adding an additional damaging pulse to charged attacks while also allowing extended flail attacks when the button is held.
Afterstrike reward details
| Reward | Effect |
|---|---|
| Afterstrike Upgrade | Adds an extra damage pulse when holding Attack and enables continued flailing while the button remains held |
The upgrade is particularly useful for players who frequently use charged attacks and want additional damage output during longer engagements.

Why the upgrade is easy to miss
Radiant Manor’s Red Chest is hidden behind multiple layers of progression requirements. Players must first obtain the Drill Diver, discover the Station Underside route, spend Vials on two separate locks, and defeat a guardian before the reward can be claimed.

Because of these requirements, many players will see the chest long before they have the tools necessary to reach it.
The Afterstrike Upgrade is one of the more valuable hidden rewards in Mina the Hollower. To obtain it, travel to Station Underside, use the Drill Diver Sidearm, spend 4 Vials to access the secret courtyard, defeat the guardian, and then spend 5 more Vials to unlock the Red Chest. Your reward is Afterstrike, a powerful upgrade that enhances charged attacks with an extra pulse of damage and extended flail functionality.