Seasonal SLS Bridge

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.

Features

When a creature spawns, the mod checks the current Seasonality season and rolls a weighted seasonal modifier.

Winter — Invernal

Cold-oriented traits are favored:

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

Spring — Primaveral

Spring favors poison, adaptation and unusual mutations:

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

Summer — Estival

Summer favors heat and aggressive elemental effects:

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

Autumn — Otoñal

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

Creatures that successfully receive a seasonal StarLevelSystem modifier receive a visual seasonal title:

• Invernal Esqueleto [Frost]
• Primaveral Greydwarf [Poison]
• Estival Draugr [Fire]
• Otoñal Greydwarf [Lightning]

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.
LogApiDiscovery	true	Logs the discovered StarLevelSystem API method.

Requirements

Required dependencies:

• BepInExPack Valheim
• Jötunn
• YamlDotNet
• StarLevelSystem
• Seasonality

The exact package versions are listed in manifest.json.

Installation

1. Install the dependencies listed above.
2. Put SeasonalSLSBridge.dll in BepInEx/plugins/SeasonalSLSBridge/.
3. Launch Valheim.

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, discovers the compatible 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 discovery problem and leaves the creature alone.

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.