Seasonal SLS Bridge 1.4.2

Seasonal SLS Bridge connects Seasonality with StarLevelSystem to give Valheim's creatures seasonal combat traits and optional visual variants.

The goal is simple: make the world feel more alive and less predictable without changing StarLevelSystem itself, replacing its modifier names, or taking control away from Seasonality.

Community & support

For mod questions, bug reports, ideas, texture contributions or general discussion, join the community Discord:

https://discord.gg/kN3cqHqWYA

What's new in 1.4.2

Version 1.4.2 is a small compatibility update adding explicit support for StarLevelSystem 1.18.0.0.

No seasonal logic, probabilities, titles, ecological behavior or visual selection rules have changed in this release. The custom visual pack from 1.4.1 remains unchanged and continues to include finished textures for the Troll, Greydwarf family and Skeletons.

Visual System

The visual system is designed to complement Seasonality instead of replacing it.

Current artwork status: fully finished public custom textures are currently included for the Troll, the Greydwarf family and Skeletons.
The broader visual framework and creature catalog are already prepared for additional families, which will continue to be added gradually.

When a supported creature has a matching modifier, Seasonal SLS Bridge can apply a local visual variant for that creature.

Examples include:

• Frost — winter / cold appearance
• Fire — heated or volcanic appearance
• FireNova — more unstable fire appearance
• Poison — toxic / overgrown appearance
• PoisonNova — unstable toxic appearance
• Lightning — storm-charged appearance
• ElementalChaos — unstable arcane appearance
• Big — winter heavy / imposing appearance where supported
• SoulEater — dark generic appearance
• Brutal — aggressive generic appearance

Unedited or unsupported properties are left alone so Seasonality can continue handling its normal seasonal visuals.

Visual priority

If a creature qualifies for more than one supported visual, the bridge uses a fixed priority:

1. Elemental modifiers, with seasonal primary elements taking priority
2. SoulEater
3. Brutal
4. Big

This keeps the result predictable and avoids multiple systems trying to overwrite the same material.

Elemental visual fallback

Elemental modifiers applied directly by StarLevelSystem can still use the matching visual even if the creature has no recorded birth season.

For visual selection only:

• Frost falls back to winter
• Fire, Lightning and FireNova fall back to summer
• Poison, ElementalChaos and PoisonNova fall back to spring

This fallback is visual only. It does not write a birth season, change titles, reroll modifiers or alter gameplay state.

Features

Every eligible new creature stores its birth season.

Season, birth biome and natural affinity determine the seasonal modifier profile.

With the default 100% gate and EnsureSeasonalModifier enabled, an otherwise empty valid roll can use a Minor seasonal fallback:

• Winter: Big
• Spring: Fast
• Summer: ResistFire
• Autumn: Alert

StarLevelSystem must still accept the selected modifier.

Winter — Vetrbarn

Cold-oriented traits are favored:

• Frost
• ResistFrost
• Big
• StaminaDrain
• ResistPierce
• ResistSlash
• ResistBlunt
• EitrDrain

Spring — Várbarn

Spring favors poison, adaptation and unusual mutations:

• Poison
• ElementalChaos
• PoisonNova
• ResistPoison
• Fast
• Evolving
• Splitter

Summer — Sumarbarn

Summer favors heat and aggressive elemental effects:

• Fire
• FireNova
• ResistFire
• Lightning
• Fast
• Brutal
• Big

Autumn — Haustbarn

Autumn favors lightning, poison and spiritual effects:

• Lightning
• Poison
• ElementalChaos
• SoulEater
• ResistSpirit
• Alert
• ResistPoison
• Big

The exact result is weighted, so not every creature receives the same modifier.

Seasonal Creature Names

Eligible new creatures retain their birth-season title independently of the modifier result:

• Esqueleto Vetrbarn
• Greydwarf Várbarn
• Draugr Sumarbarn
• Greydwarf Haustbarn

The bridge does not rewrite StarLevelSystem's modifier names.

The seasonal title is added separately to the creature's hover name.

Screenshots

The Troll screenshots below remain the current public showcase. Version 1.4.1 also includes completed custom textures for the Greydwarf family and Skeletons.

Fire — Sumarbarn

SoulEater

Poison — Várbarn

Elemental Chaos

Lightning — Haustbarn

Frost — Vetrbarn

Configuration

Configuration file:

BepInEx/config/TheLionCid.SeasonalSLSBridge.cfg

Main settings:

Existing configuration can be kept when updating. New settings are added automatically.

Custom textures

The visual pack is intentionally lightweight and editable.

Personal PNG edits are preserved by the texture preparation workflow, making it possible to build custom or HD visual packs without changing the gameplay logic of the bridge.

The compact package includes the required texture bases and Preparar-Texturas.ps1 to recreate the editable texture tree.

Requirements

Required dependencies:

• BepInExPack Valheim
• Jötunn
• YamlDotNet
• StarLevelSystem
• Seasonality

Explicitly verified StarLevelSystem versions:

• 1.14.0.0
• 1.15.0.0
• 1.16.0.0
• 1.17.0.0
• 1.18.0.0

Other versions are not automatically assumed to be compatible.

Installation

Thunderstore

Install Seasonal SLS Bridge and its dependencies through your mod manager.

For the best multiplayer experience, use the same mod version and visual files on the server and clients.

Manual installation

1. Install the required dependencies.
2. Place SeasonalSLSBridge.dll in:

BepInEx/plugins/SeasonalSLSBridge/

1. Place the SeasonalTextures folder alongside the DLL.
2. If using the compact texture package, run Preparar-Texturas.ps1 to generate the editable visual variants.
3. Remove the old experimental TextureTest add-on if it is still installed.
4. Launch Valheim.

Existing creatures are not rerolled when updating.

Only the appropriate server authority applies gameplay changes. Players, bosses, traders and, by default, tamed creatures remain excluded from seasonal modifier application.

Compatibility and design

Seasonal SLS Bridge is intentionally a bridge between existing mods.

It does not:

• modify StarLevelSystem's internal modifier definitions;
• replace StarLevelSystem modifier names;
• edit creature stats directly;
• change spawn rates;
• change loot;
• require manual editing of StarLevelSystem configuration;
• alter Seasonality's season system;
• write network gameplay state just to display a visual variant.

The visual system is local and cosmetic. If a supported texture cannot be loaded, gameplay should continue with the normal creature appearance.

Stability

If the expected StarLevelSystem API cannot be found, the bridge does not attempt unsafe internal modifications.

It reports the compatibility problem and skips modifier application. The creature's stored seasonal identity remains independent from modifier success.

Support, feedback and contributions

The community Discord is linked near the top of this README. Contributions and feedback are welcome, especially from experienced Valheim/BepInEx modders and texture artists.

AI-assisted development

A significant part of this mod's development, including code generation, debugging, compilation assistance, testing and troubleshooting, was done with the help of AI.

The author, TheLionCid, is not an experienced Valheim mod developer and is publishing this project openly so that more experienced modders can review it, identify problems and help improve it.

Feedback, bug reports and code improvements are welcome.

Permissions

You may adapt or modify this project for your own use, provided that you respect the licenses and credits of this project and its dependencies.

Do not redistribute the work of other authors as your own.

Credits

• TheLionCid — Seasonal SLS Bridge
• MidnightMods — StarLevelSystem
• RustyMods — Seasonality
• ValheimModding — Jötunn and YamlDotNet
• BepInEx / Valheim modding community — modding framework and ecosystem

Disclaimer

This is an independent compatibility bridge. It is not an official component of StarLevelSystem or Seasonality.

Updates to Valheim, StarLevelSystem or Seasonality may require an update to the bridge.

Changelog

1.4.8

• Verified compatibility with StarLevelSystem 1.18.2.
• Future StarLevelSystem versions with a compatible public API can continue working with a single startup warning instead of being rejected only because the version number is newer.
• Real API incompatibilities still disable the StarLevelSystem integration safely and report the problem.
• The validated public StarLevelSystem API is now bound through delegates, avoiding direct calls to functions that may be absent in future versions.
• Added local seasonal icons next to creature hover names for winter, spring, summer and autumn.
• Added Titles.ShowSeasonTitle so Vetrbarn, Várbarn, Sumarbarn and Haustbarn can be hidden while keeping the seasonal icon visible.
• Added Titles.ShowSeasonIcon, Titles.SeasonIconSize and Titles.SeasonIconSpacing for local seasonal-icon UI control.
• Seasonal icons use 128×128 RGBA PNG assets and remain purely local/cosmetic: they do not modify ZDO data, StarLevelSystem state or network authority.

1.4.7

• Documentation-only update.
• No gameplay, seasonal, ecological or visual-system behavior changed in this release.

1.4.6

• Verified compatibility with StarLevelSystem 1.18.1 using a local assembly reference and contract tests.
• Added visual inheritance for BalrondHumanoidRandomizer Skeleton and Draugr variants: supported randomized variants reuse the texture set of their catalogued base creature without duplicating texture files or pulling excluded base prefabs back into the visual catalog.
• Fixed visual-property filtering so unrelated material/property blocks no longer prevent supported texture maps from being applied.
• Added a retry path when the first visual application attempt fails, with clearer warnings that include the affected prefab name.
• Big visuals are now available year-round where supported.
• Supported autumn visual variants can now act as an out-of-season fallback where appropriate.
• Visual priority remains unchanged: elemental modifiers → SoulEater → Brutal → Big.

1.4.2

• Added compatibility with StarLevelSystem 1.18.0.0.
• No gameplay, seasonal, ecological or visual-content changes in this release.

1.4.1

• Added compatibility with StarLevelSystem 1.17.0.0.
• Added new custom visual textures for the Greydwarf family.
• Added new custom visual textures for Skeletons.
• Improved and corrected several existing Troll textures for better visual consistency and UV alignment.
• Updated the public visual pack to reflect the newly completed creature families.
• Updated documentation and dependency information for the 1.4.1 release.

1.4.0

• Added the new optional creature visual system, allowing supported StarLevelSystem modifiers to have matching local appearances.
• Current public texture pack: only the Troll has fully finished custom textures for now; additional creature families will be added gradually.
• Added a visual framework/catalog prepared for 23 creature families / 38 prefabs.
• Added support for seasonal visual combinations such as FireNova, PoisonNova and winter Big.
• Added generic SoulEater and Brutal visual variants that can work in any season.
• Elemental modifiers applied directly by StarLevelSystem can now use their matching visual even when the creature has no recorded birth season.
• Added deterministic visual priority: elemental modifiers first, then SoulEater, Brutal and Big.
• Added support for body textures, eye textures, emission masks and HDR material colors while leaving unsupported or unedited properties to Seasonality.
• Added Point texture filtering by default to preserve Valheim's pixel detail, with optional Bilinear and Trilinear filtering for HD texture packs.
• Personal texture edits are preserved by the texture preparation workflow.
• Added explicit compatibility with StarLevelSystem 1.16.0, while keeping support for 1.14.0 and 1.15.0.
• The visual system is cosmetic only and does not change modifier probabilities, seasonal titles, creature stats, authority rules, spawn rates, loot or network gameplay state.
• Existing creatures are not rerolled when updating.
• Added the community Discord for mod support, feedback and contributions: https://discord.gg/kN3cqHqWYA

1.3.1

• Added support for StarLevelSystem 1.15.0 while keeping compatibility with 1.14.0.
• Improved seasonal identity persistence. Creatures now keep their birth-season identity even when they do not receive a seasonal modifier.
• Seasonal titles are now independent from modifier application, making seasonal creatures more consistent across different configurations and situations.
• Added a new optional seasonal fallback system. When a seasonal roll would otherwise result in no modifier, the creature can receive a Minor trait associated with its season:
  • Winter: Big
  • Spring: Fast
  • Summer: ResistFire
  • Autumn: Alert
• The seasonal fallback system is enabled by default and can be disabled with EnsureSeasonalModifier.
• Creatures that already have the selected modifier will keep it without receiving a duplicate.
• Improved compatibility handling with StarLevelSystem to prevent unwanted additional modifier attempts when an application fails.
• Existing ecological profiles, biome and creature affinities, seasonal probabilities, filters and multiplayer behavior remain unchanged.
• Existing creatures are not retroactively rerolled or given a new birth-season identity.
• Improved overall stability, diagnostics and testing.

1.3.0

• Added a new ecological affinity system: seasonal modifiers can now vary depending on the creature's biome and natural affinity.
• Added 36 biome profiles and six natural affinities.
• Added optional per-creature affinity overrides through the configuration file.
• Reduced Poison and PoisonNova in early-game environments, while naturally poisonous creatures can still receive them normally.
• Creatures now keep the seasonal identity of the place and season in which they spawned.
• Seasonal titles are now displayed after the creature's name.
• Added support for StarLevelSystem 1.15.0 while keeping compatibility with 1.14.0.
• Improved StarLevelSystem compatibility checks and overall stability.
• Expanded testing and diagnostics for seasonal probabilities and ecological profiles.

1.2.0

• Updated integration to use the official StarLevelSystem 1.14.0 API for safer and more reliable modifier application.
• Improved multiplayer handling so seasonal modifiers are applied only by the appropriate server authority.
• Reworked seasonal probabilities: primary modifiers now use their actual configured percentages, while secondary modifiers are selected from the remaining chance.
• Added persistent seasonal identities. Creatures that successfully receive a seasonal modifier now keep their seasonal title after saving, loading, or changing seasons.
• Added new Norse-inspired seasonal titles:
  • Winter: Vetrbarn
  • Spring: Várbarn
  • Summer: Sumarbarn
  • Autumn: Haustbarn
• Improved spawn detection so newly spawned creatures are distinguished from creatures being loaded from an existing world.
• Existing creatures are not retroactively rerolled or modified when updating to 1.2.0.
• Improved internal stability, build validation, and automated testing.

1.1.1

• Added the project's GitHub repository link to the Thunderstore manifest.
• Documentation and source repository information updated.

1.1.0

• Added seasonal visual creature titles:
  • Invernal
  • Primaveral
  • Estival
  • Otoñal
• Titles are applied without changing StarLevelSystem modifier names.
• Added cleanup when creatures are destroyed.
• Kept the stable seasonal modifier bridge architecture.

1.0.0

• Initial release.
• Seasonal weighted StarLevelSystem modifiers.
• Seasonality integration.
• Configurable roll chance, delay, tamed-creature handling and logging.