BalrondNegativeSkills

Current version: 0.1.5

BalrondNegativeSkills extends Valheim's normal skill range from 0..100 to -100..100.

A negative skill is not only a displayed number. Below zero, the mod turns the skill into a real gameplay penalty. The intended idea is that a character can become worse than an untrained level-0 character and must relearn basic competence before normal progression resumes.

-100  <----------------  0  ---------------->  100
 severe deficiency      baseline              mastery

Main rules

• Positive skills 0..100 remain vanilla wherever possible.
• Negative values are stored in Valheim's normal character skill save data.
• Raw values are clamped to -100..100 on save/load.
• A negative skill can recover through normal skill XP.
• When the skill reaches 0, normal vanilla progression resumes.
• Negative skills do not count as negative credit against Valheim's total skill cap by default.

Signed skill factor

For calculations that normally use Skills.GetSkillFactor(), the mod exposes a signed factor below zero.

With default settings:

Skill	Factor
0	0.00
-25	-0.25
-50	-0.50
-75	-0.75
-100	-1.00

Negative Effect Multiplier can scale this negative branch without changing positive vanilla skill behavior.

What negative skills affect

The mod extends the existing Valheim formulas rather than inventing a separate stat system.

Examples:

• weapon skills: lower damage/knockback and higher stamina/eitr/health costs where the vanilla attack uses that skill;
• Blocking: lower block power;
• Jump: lower jump force;
• Run: lower run speed and higher stamina drain;
• Swim: higher stamina drain;
• Sneak: worse stealth and higher stamina drain;
• Dodge: higher stamina cost;
• Bows: negative skill extends the existing bow draw-time penalty path;
• Crossbows and other skillAccuracy projectile attacks: negative skill now extrapolates accuracy below the level-0 baseline instead of being clamped by Mathf.Lerp;
• Riding: lower mount performance and higher stamina usage through the signed rider-skill path;
• Crafting/Cooking: skill-scaled actions take longer and tool/action costs can increase;
• Farming: harvest radius can shrink and tool costs can increase;
• Fishing: performance can become worse and stamina costs can rise, with a safety floor preventing invalid negative/zero speeds.

Chance-only positive bonuses such as extra yield simply stop occurring below zero unless the underlying Valheim mechanic has a meaningful negative counterpart.

Blood Magic safety

Blood Magic contains several vanilla formulas that use the numeric skill level directly instead of GetSkillFactor(). Extending those formulas blindly below zero can produce zero or negative values.

Version 0.1.2 adds dedicated protection:

Summons

Vanilla copied summon performance uses a formula equivalent to:

1 + skillLevel * prefabCopyFactor

At sufficiently negative Blood Magic this could reach zero or become negative, causing nonsensical damage or inverted knockback.

For negative Blood Magic only, BalrondNegativeSkills remaps this branch so the entire negative range approaches a safe configurable floor.

Default:

Blood Magic 0     -> 100% of level-0 summon multiplier
Blood Magic -100  -> minimum 25%

Positive Blood Magic continues using the original prefab coefficient.

Protection shields

SE_Shield also scales absorb capacity directly from skill level. Negative Blood Magic could otherwise create a zero/negative barrier.

For Blood-Magic shields, the negative range is remapped from the normal level-0 absorb value down to a configurable positive floor.

Default floor: 25% of the level-0 base absorb value, before world-level additions.

Death skill loss

Hard death vs soft death

Valheim does not lower skills on every death.

Player.OnDeath() applies Skills.OnDeath() only when the death is a hard death. A death during Valheim's hard-death cooldown is a soft death and does not reduce skills. BalrondNegativeSkills preserves that vanilla rule.

The current Valheim player field uses a 10-second hard-death cooldown. Because respawning itself takes time, rapid test deaths can still land on the boundary. For testing, wait a little after respawning before killing the character again.

Why 0.1.1 looked stuck at -1

Version 0.1.1 used the percentage death factor even very close to zero. The UI floors negative values:

raw -0.05 -> displayed -1
raw -0.50 -> displayed -1
raw -0.99 -> displayed -1
raw -1.01 -> displayed -2

Therefore repeated deaths could change the saved raw skill while the visible integer stayed at -1 for a long time.

New 0.1.2 behavior

The new setting:

Minimum Negative Loss Per Hard Death = 1.0

means that, by default, every qualifying hard death removes at least one full raw skill point when the skill is already <= 0 or is inside the zero-crossing band.

The normal percentage loss still wins when it is larger.

Default example starting exactly at zero:

hard death #1:  0  -> -1
hard death #2: -1  -> -2
hard death #3: -2  -> -3

At deep negative values, percentage loss can become larger than one point and progression toward -100 accelerates.

Every time this mod actually handles Skills.LowerAllSkills, BepInEx logs a compact line like:

[BalrondNegativeSkills] Applied hard-death skill loss: factor=..., minimumNegativeLoss=1, changedSkills=..., negativeSkills=...

If that line is absent for a death, the mod's hard-death skill-loss patch was not invoked for that death (for example because it was a vanilla soft death).

Enable Diagnostics = true to log each changed skill with raw before/after values.

Negative skill UI

Valheim's vanilla Skills window casts raw skill level directly to an integer. C# truncates negative fractions toward zero, so raw -0.25 was displayed as 0.

BalrondNegativeSkills uses floor semantics for negative labels, matching Skills.GetSkillLevel():

raw -0.25 -> displayed -1
raw -1.25 -> displayed -2

Version 0.1.2 also refreshes an already-open Skills dialog immediately after the mod applies skill loss.

Relearning a negative skill

Vanilla Skills.Skill.Raise() is not safe for negative levels because its level requirement formula assumes a non-negative skill.

BalrondNegativeSkills replaces only the negative branch.

Recovery uses vanilla requirement values in reverse deficit order:

raw -100 -> next recovery step uses approximately the vanilla level-100 requirement
raw  -50 -> next recovery step uses approximately the vanilla level-50 requirement
raw   -1 -> next recovery step uses approximately the vanilla level-1 requirement
raw    0 -> vanilla progression resumes

A recovery step can never grant free positive levels while crossing zero.

Saving and relogging

Valheim serializes each skill's raw level as a floating-point value in the normal character save. The vanilla save/load code does not itself clamp that float to zero.

BalrondNegativeSkills therefore does not create a duplicate ZDO/custom-data database. It keeps the normal Skills.Save/Load data authoritative and clamps only to -100..100.

Negative skill values persist across logout/relogin while the mod is installed.

Keep character backups while testing mods that alter core skill data.

Console testing

Valheim's existing raiseskill command is extended for negative values and for raising an already-negative skill.

Examples:

raiseskill swords -25
raiseskill blocking -50
raiseskill bloodmagic -100
raiseskill crossbows -25

For a quick persistence test:

1. enable devcommands;
2. set a skill negative;
3. verify it in the Skills window;
4. logout and reload the character;
5. verify the negative value is still present.

Configuration

Generated at:

BepInEx/config/balrond.astafaraios.BalrondNegativeSkills.cfg

Important settings:

Setting	Default	Purpose
Lock Configuration	true	ServerSync lock; server controls synchronized gameplay settings while connected
Enabled	true	Master switch
Negative Effect Multiplier	1.0	Scales penalties below zero
Death Can Cross Zero	true	Allows death loss below zero
Zero Crossing Band	1.0	Positive near-zero range allowed to use the crossing/minimum loss
Minimum Negative Loss Per Hard Death	1.0	Minimum raw loss for zero/negative skills on a qualifying hard death
Prevent Negative Skill Cap Credit	true	Negative skills do not create extra positive skill-cap capacity
Minimum Harvest Radius Multiplier	0.25	Farming safety floor
Minimum Fishing Performance Multiplier	0.25	Fishing safety floor
Minimum Blood Magic Summon Multiplier	0.25	Prevents zero/negative summon performance
Minimum Blood Magic Shield Multiplier	0.25	Prevents zero/negative Blood Magic shield capacity
Diagnostics	false	Detailed per-skill and safety-patch logging

ServerSync and multiplayer

BalrondNegativeSkills 0.1.5 uses ServerSync for gameplay configuration.

The following settings are synchronized from the server:

• Enabled
• Negative Effect Multiplier
• Death Can Cross Zero
• Zero Crossing Band
• Minimum Negative Loss Per Hard Death
• Prevent Negative Skill Cap Credit
• Minimum Harvest Radius Multiplier
• Minimum Fishing Performance Multiplier
• Minimum Blood Magic Summon Multiplier
• Minimum Blood Magic Shield Multiplier

Diagnostics is intentionally local because it only controls logging on the current machine.

Lock Configuration defaults to true. With the lock enabled, connected clients use the server values for all synchronized gameplay settings. Install the same BalrondNegativeSkills version on the server and every client.

The stable plugin GUID remains:

balrond.astafaraios.BalrondNegativeSkills

ServerSync is merged into the final BalrondNegativeSkills.dll by ILRepack. A normal completed build should not leave a separate ServerSync.dll in bin/Release.

Existing config files

Updating does not require deleting the old config. BepInEx will add the new ServerSync Lock Configuration entry automatically. Existing gameplay values remain valid.

Compatibility with custom skills

Core storage/recovery patches operate on Skills.Skill and therefore also support registered custom skill values below zero.

If another mod calculates its effect through Skills.GetSkillFactor(), it receives the signed factor automatically.

If another mod reads m_level/GetSkillLevel() directly and implements its own formula, that formula may need its own negative-value handling. This is relevant for custom systems such as BalrondExtraSkills.

Public integration API

Namespace:

BalrondNegativeSkills.API

Example:

float raw = NegativeSkillsApi.GetRawLevel(player, Skills.SkillType.Swords);
float penalty = NegativeSkillsApi.GetPenaltyFactor(player, Skills.SkillType.Swords);

float result;
NegativeSkillsApi.TrySetLevel(player, Skills.SkillType.Swords, -40f, true, out result);
NegativeSkillsApi.TryModifyLevel(player, Skills.SkillType.Swords, -5f, true, out result);

Installation

1. Install BepInEx for Valheim.
2. Build or obtain BalrondNegativeSkills.dll.
3. Place it in:

BepInEx/plugins/BalrondNegativeSkills/BalrondNegativeSkills.dll

1. Start Valheim.

For multiplayer testing, use the same mod version/config on participating clients and the server where applicable.

Design rule

The mod deliberately avoids replacing the complete Valheim skill system.

For effective skill values >= 0, vanilla remains authoritative. Custom behavior is added only where negative values require signed extrapolation, negative progression, or a safety floor to prevent invalid game state.

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