BossAdd

BossAdd adds new mechanics and phase patterns to all 7 Valheim bosses.
Every feature is fully configurable via BepInEx ConfigurationManager (F1 key).
Supports English and Korean — auto-detected from your Valheim language setting.

Features

Eikthyr

• Summon — Calls minions on HP thresholds, timer intervals, or both. Includes a special elite summon at low HP.
• Stomp Lightning — Stomp attacks trigger lightning strikes with a configurable burning DoT on hit and a safe zone radius.
• Horn Attack — Horn charge launches players with force matching the boss's actual melee attack range. Blocked while the player is dodge-invincible.
• Phase Messages — Custom HUD messages at configurable HP thresholds.

The Elder

• Tree Spawn — Grows trees around players when below HP threshold.
• Rock Throw Combo — The root-shoot attack triggers a configurable burst of boulder throws (count and interval), each with splash damage on impact.
• Phase Messages — Custom HUD messages.

Bonemass

• Split Summon — Splits into 5 MiniBonemass variants at HP threshold.
• Kill Condition — Bonemass cannot die until all MiniBonemass are defeated. Wrong kill order heals Bonemass.
• Mini Stats — Customize MiniBonemass HP, damage, speed, attack range, and damage resistances independently.
• Throw Summon — Throw attacks have a chance to spawn additional minions.
• Phase Messages — Custom HUD messages.

Moder

• Frost Clones — Splits into MiniModer clones at HP threshold.
• Mini Stats — Customize MiniModer scale, HP, damage, speed, and flight behavior.
• Air Breath — Fires frost breath while airborne.
• Landing Blast — Knocks back nearby players on landing.
• Freeze Roar — AOE frost attack triggered below HP threshold.
• Ice Field — Creates a persistent frost damage zone.

Yagluth

• Skeleton Summon — Summons Skeleton Warriors at 3 HP thresholds. While any Skeleton lives, Yagluth takes no damage.
• Death Zone — Forces a nova slam at HP threshold. Drains % max HP from all nearby players. VFX and radius configurable.
• Meteor Fire Patch — Meteor impacts leave lasting fire fields.
• Rage Mode — Accumulated damage triggers a berserk state with speed and damage bonuses.

The Queen

• HP Summon — Spawns brood at configurable HP intervals.
• Timer Summon — Spawns brood on a repeating timer during combat.
• Breath Summon — Breath attacks trigger additional minion spawns.
• Poison Field — Creates persistent poison damage zones along her movement path.

Changelog

v1.0.4

• Eikthyr — Removed the Fire Patch mechanic entirely.
• Eikthyr — Horn Attack launch range now matches the boss's actual melee attack range instead of a separate config value.
• Eikthyr — Horn Attack no longer launches players while they are dodge-invincible.
• Eikthyr — Removed the lightning telegraph (warning) delay and the lightning slow (shock) effect. The lightning burn DoT is unchanged.
• Eikthyr — Fixed a crash in Horn Attack caused by accessing a private ZNet field directly.
• All Bosses — Fixed a serious bug where HP, movement speed, and attack speed multipliers kept stacking every time a boss's zone reloaded (e.g. after a player died or reconnected mid-fight), eventually making bosses effectively unkillable or hyper-aggressive. Multipliers are now always calculated from a cached original value instead of the current (already-modified) one. Affects all 7 bosses.
• The Elder — Rock Throw is no longer an independent cooldown/chance-based ability. It now triggers as a configurable burst combo (count + interval) whenever the root-shoot attack fires.

Requirements

• BepInEx for Valheim

Compatibility

BossAdd works with vanilla Valheim + BepInEx only — no monster database mods required.
All boss modifications (size, HP, damage, resistances) are handled internally via config values.

Note: Using BossAdd together with monster stat mods such as CLLC (CreatureLevelAndLootControl) may cause stat conflicts on mini-bosses (MiniBonemass, MiniModer). This is not officially supported.

Installation

Install via r2modman or Thunderstore Mod Manager (recommended).
Manual install: extract to BepInEx/plugins/bossadd/.

Configuration

Open the F1 menu in-game to adjust all settings per boss.
All features can be individually enabled or disabled.
Config file: BepInEx/config/bossadd.cfg

Language Support

The F1 menu descriptions automatically display in English or Korean
based on your Valheim language setting (Main Menu → Settings → Language).

Bug Reports & Support

Found a bug? Please report it so it can be fixed!

Join the Discord server via the Support section on the CaptainSkillTree mod page.
Post your report in the appropriate channel — responses are active.

When reporting, please include:

• What happened and what you expected
• Your mod list (other mods installed)
• The BepInEx log file (BepInEx/LogOutput.log)