How to Unlock Nightmare in Hero Siege Season 10

Act 8 is now part of the base-game progression. Act 9, Ebontharn, follows after defeating Odin in Act 8. The official announcement does not publish a complete difficulty-unlock walkthrough.

A recent community walkthrough reports that completing Normal through Act 9 and defeating Cthulhu unlocks Nightmare, while defeating Cthulhu again in Nightmare unlocks Hell. Treat this as a community-verified route, not an official rulebook, and check patch notes if your quest state differs.

Use the Act 9 minimap and NPC indicators added in 7.0.2, confirm that your game is updated, then consult the official announcement or current community reports. Do not assume a pre-Season-10 difficulty guide still applies.

The official Season 10 announcement confirms the structural change: Act 8 is now part of the base game, and Act 9 Ebontharn follows after Odin. It does not publish a step-by-step Nightmare unlock rule. The detailed Normal to Nightmare and Nightmare to Hell path on this page comes from a current community walkthrough. That distinction is deliberate. It tells you what the developer has confirmed and what players have observed after launch.

This matters because older Hero Siege guides use different acts, bosses, and difficulty requirements. A search result from an earlier season may still rank well while describing a route that no longer applies. Check the publication date, check whether it mentions Ebontharn, and prefer a source that labels its patch window. If two current reports conflict, do not choose the more confident one. Test the in-game objective and look for a recent official fix or announcement.

Begin by treating the campaign as the prerequisite rather than a detour. Finish your available Normal progression, complete Act 8, defeat Odin, and enter Act 9. In the current community route, defeating Cthulhu at the end of Normal Act 9 unlocks Nightmare. Do not skip quest state checks after a boss. A portal, an NPC conversation, or a completion marker can be the difference between a true unlock and a fight that did not register correctly.

When Nightmare opens, confirm that the difficulty is selectable before spending time on a long farming loop. If the option is missing, record the difficulty, act, boss, and any quest marker still visible. Then check the current patch notes and current community discussions. This produces a useful troubleshooting report and avoids repeating a full campaign because of an unclear assumption.

The same community walkthrough reports that defeating Cthulhu again in Nightmare unlocks Hell, with level 100 named as the practical progression point. Treat the level and boss sequence as community guidance, not a developer-published requirement. The safest approach is to use it as a checklist, then verify your own game state after the kill.

Do not rush into a higher difficulty simply because the button appears. Review your damage, defenses, movement, recovery, and ability to handle a boss encounter without repeated deaths. A difficulty unlock opens options; it does not prove that the character is ready to farm efficiently there. If the build is based on an archived Season 9 guide, label that assumption and use current Season 10 patch information before making expensive gear or respec decisions.

Patch 7.0.2 added NPC indicators and minimap guidance for Act 9 quests. Start there before consulting a video. Make sure the game is updated, open the map, revisit the marked NPC or zone, and complete any visible conversation or interaction before assuming the quest is bugged. Keep screenshots of your objective text and map marker if you ask for help.

Community route details such as named locations, exact NPC positions, and boss behavior can be useful, but they are the most likely parts to age after a hotfix. This page does not turn those observations into permanent facts. The Ebontharn guide provides the official Act 9 context; this page is the decision aid for moving between difficulties.