Hero Siege Season 10 Ebontharn - What Changed

Season 10 is named Ebontharn, and it launched on 21 August 2026 across Steam, PlayStation 5 and Android. Its announcement framed it simply:

Set sail to Ebontharn, and uncover the mystery of this ancient land.

What did Season 10 add?

Act 9, Ebontharn — a new act, free to base-game owners, reached after defeating Odin in Act 8.

Three new Uber Bosses — Phantom Leviathan, Captain Grimtide and Blood Maiden. The Tablet of Armada route explains how the Grimtide key drops and where it is used in Shipwreck Cove.

The Abyssal Chest — a new permanent map mechanic that can generate on almost any map. It is guarded by five lock symbols and cannot be opened until you open surrounding chests found by following dark erosions in the ground.

Satanic zone drop buffs, which are the change most likely to affect your farming directly:

Buff	Change
Magic find (all 3 satanic zone tiers)	+100% magic find on top of existing
Rune drop, Inferno / Hell 5	25% → 35%
Angelic drop, Inferno / Hell 5	20% → 28%

How does the Abyssal Chest work?

The mechanic rewards commitment rather than a quick grab:

1. You will see dark erosions in the ground before you reach the chest, each trailing off toward a surrounding chest.
2. The Master Chest sits at the centre, guarded by five lock symbols, and is not openable on arrival.
3. Opening a surrounding chest immediately spawns a large pack of extremely difficult enemies on top of you.
4. Only one surrounding chest is required to unlock the master chest — but opening more increases the loot, so coverage is strongly recommended if you can survive it.

One documented limitation: the Abyssal Chest cannot be buffed by your Ether Tree, unlike other map mechanics. There is currently no way to increase its spawn chance.

What is coming after Season 10?

The developer stated plans to begin work on Act 8 — Gates of Valhalla after the season released, along with a complete overhaul of the questing system.

Note the numbering reads oddly against Act 9 already existing; the announcement is quoted as written. Treat the roadmap as direction rather than a schedule.

What about the paid content in Season 10?

Cosmetic lootboxes with Steam Marketplace integration. Keys cost $1.49, and the items are tradable and sellable on the Steam Marketplace. Legendary (orange) items drop at 20%.

The developer framed this as supporting free content: most of what they ship is free to base-game owners, with cosmetics funding it. That is consistent with the Season 9 decision to make six previously paid classes free.

For chronology, start with the Season 10 release page. The Ether Tree guide explains why its buffs do not reach the Abyssal Chest, and the Helheim route covers the Act 8 gate before Ebontharn. Check the patch summary and price-check guide before using launch drop rates to make current farming or trading decisions.

Next step

If you are returning for Season 10, the satanic zone drop buffs change where farming pays best — and Act 9 needs Odin in Act 8 cleared before you can reach it.