Seasonal SLS Bridge 1.3.1

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

The goal is simple: make the world feel more alive and less predictable without changing StarLevelSystem itself or replacing its own modifier names.

What's new in 1.3.1

This public release combines the fixes and improvements developed after 1.3.0 into a single 1.3.1 update.

• Explicit support for StarLevelSystem 1.14.0 and 1.15.0.
• Seasonal identity is now stored independently from modifier success.
• Seasonal titles survive empty rolls, rejected modifiers, API errors, and a 0% modifier gate.
• New EnsureSeasonalModifier option, enabled by default, provides a Minor seasonal fallback when a valid roll would otherwise be empty.
• Existing modifiers are respected and are not duplicated.
• Improved compatibility validation, diagnostics, and automated testing.

Features

Every eligible new creature stores its birth season. Season, birth biome and affinity determine the modifier profile. With the default 100% gate and EnsureSeasonalModifier enabled, otherwise empty valid rolls select a Minor backup: winter Big, spring Fast, summer ResistFire, autumn Alert. SLS must still accept the application.

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.

Configuration

Configuration file:

BepInEx/config/TheLionCid.SeasonalSLSBridge.cfg

Available settings:

Setting Default Description

SeasonalRollChance 100 Percentage chance for a spawned creature to receive a seasonal modifier.

DelaySeconds 0.75 Delay before the seasonal modifier is applied after spawning.

IncludeTamed false Whether tamed creatures can receive seasonal modifiers.

LogAppliedModifiers true Logs successful seasonal applications.

EnsureSeasonalModifier true Fills empty valid rolls with the seasonal Minor backup, including when profile weights are zero. False restores empty rolls.

Requirements

Required dependencies:

• BepInExPack Valheim
• Jötunn
• YamlDotNet
• StarLevelSystem
• Seasonality

StarLevelSystem 1.14.0.0 and 1.15.0.0 are explicitly verified. Other versions fail the API contract check.

Installation

1. Install the dependencies listed above.
2. With the game closed, replace the old DLL with artifacts/1.3.1/SeasonalSLSBridge.dll in BepInEx/plugins/SeasonalSLSBridge/.
3. Launch Valheim.

Keep the existing configuration; the new setting is added automatically. Existing creatures are not rerolled. Only the server owning the creature ZDO applies changes; players, bosses, traders and (by default) tamed creatures are excluded.

For a Thunderstore package, the DLL should be inside the package's plugins folder.

Compatibility and design

Seasonal SLS Bridge is intentionally designed as a small bridge between existing mods.

It does not:

• modify StarLevelSystem's internal modifier definitions;
• replace StarLevelSystem modifier names;
• edit creature stats directly;
• require manual editing of StarLevelSystem configuration;
• alter Seasonality's season system.

The bridge waits for the creature to exist, validates the exact StarLevelSystem modifier API, and then applies one weighted seasonal modifier.

Tamed creatures are excluded by default.

Stability

If the expected StarLevelSystem API cannot be found, the bridge does not attempt unsafe internal modifications. It reports the contract problem and skips modifiers. The birth-season title is still retained.

AI-assisted development

A significant part of this mod's development, including code generation, debugging, compilation assistance 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.

If you are an experienced Valheim/BepInEx modder and see a better or safer way to implement something, feedback 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.

If an update to Valheim, StarLevelSystem or Seasonality changes their APIs, this bridge may require an update.

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.