Voltfin

A playable Eel boss and a small, working example of what you can build with BossMakerAPI. Dodge its Static Lance, then face a faster Overcharge phase. The same readable design is explained in the API's creator tutorial.

Voltfin is a separate content mod. BossMakerAPI alone installs no bosses, and Voltfin does not require Devourer of Light. Installing Voltfin adds this encounter; studying or copying the source is optional.

Installation

Install BepInExPack 5.4.2305, BossMakerAPI 0.10.4, and Voltfin 1.3.2 with your Thunderstore-compatible mod manager. For manual installation, install the two dependencies separately and extract this package into the game folder, with the game closed. Its only plugin is BepInEx/plugins/Voltfin/Voltfin.dll.

The host and every client need the same API and selected content builds. Install Voltfin on every peer, not just the host. ModMenu is optional and is neither bundled nor required. No game binaries, game assets, framework DLLs or CFG files are included in this package.

If you used the private friend kit, keep only one installed Voltfin DLL. This release preserves its existing plugin GUID, boss ID and CFG filename; do not install an extra renamed copy of the unmodified creator starter beside it. Back up worlds before changing the mod set, and update all peers together.

The encounter

• Each eligible Eel catch has a configurable 10% chance to become Voltfin. Catch attempts are repeatable; there is no trigger cooldown or session cap. Normal rod, bait and location rules still decide whether you catch an Eel.
• The boss starts with 2,500 base HP, before game difficulty scaling, and 1.2x physical scale. It keeps native Eel movement and contact damage.
• Static Lance marks a fixed 12-metre-long, 2-metre-wide lane toward a nearby eligible player. Its cyan-and-white warning lasts 1.2 seconds, then deals 8 damage by default. Step sideways: the warning does not track you.
• Charged is the starting phase. Overcharge begins at 50% HP, reducing the post-cast cooldown from 6 to 3 seconds. Including the warning and recovery, default cast starts are roughly 8 seconds apart, then 5 seconds apart.
• The fight uses the native mini-boss health bar and 15-minute timer. Its corpse is worth 2x an equivalent vanilla Eel before normal weight, cooking and other value modifiers. There is no extra drop or fixed sale price.

The ability adds no projectile, stun, electrical status, dash or replacement AI. Its recovery delays the next ability but does not freeze native Eel movement. The hit volume extends 4 metres vertically above and below the line's origin; it does not automatically raycast cover. Target availability and scheduling can delay a cast. A phase change cancels the old cast and its phase-local schedule.

The API looks for clear water 8-12 metres from the authenticated fishing rod. An occupied native boss slot, incompatible peer or unsafe placement preserves the original fish. After a successful replacement, the fish is consumed and empty-bait return is a separate delivery; a delayed return does not create another boss or restore the fish. Voltfin is not left attached to the rod.

Configuration and optional menu

First launch creates BepInEx/config/example.howtofish.voltfin.cfg. The example prefix is retained deliberately so existing settings and saves keep their identity.

The host controls these five gameplay values for the session without overwriting client CFG files. Accepted live edits apply to future catches and newly spawned bosses; an active Voltfin keeps its captured balance. A client's menu displays local preferences, not the host's effective values. Check the API log if an edit is queued or rejected.

BaseHealth is base HP, before native difficulty: Easy ×0.75, Normal ×1, Hard ×1.25. The default 2,500 becomes 3,125 HP on Hard, so the combat bar can legitimately show more than the menu value. Voltfin disables the separate extra-player HP multiplier. Live health changes apply only to new encounters.

Optional ModMenu controls offer health choices 500-10,000 by 100, damage 1-50, whole-percent chance, and cooldowns 3-15 seconds by 0.5. Technically valid older values outside these controls remain unchanged until edited. The full CFG ranges are HP 1-100,000, damage 1-1,000, chance 0-100%, and cooldowns 3-30 seconds. A 100% chance still does not bypass fishing, placement or compatibility checks.

Host-only F8 test summon

In this mod's Testing section, EnableTestSummon is false by default. Enable it to use TestSummonKey (F8) at TestSummonDistance (8 metres; 2-20 allowed). Only the host may summon. Face clear shallow water near sea level. This shortcut belongs to Voltfin, not to an API-wide keyboard listener. It is a learning/testing convenience, not a test of Eel fishing or rod return.

Learn to build your own boss

The installed BossMakerAPI package includes the complete editable source in:

BepInEx/plugins/BossMakerAPI/docs/examples/Starter/

Start with YOUR_FIRST_BOSS.md, which explains this encounter in four blocks. VoltfinPlugin.cs demonstrates public Contracts APIs, two phases, a telegraphed ability, catch replacement, live host settings and an opt-in test shortcut. Voltfin.csproj, MenuConfiguration.cs, a license and a creator packager are included. You do not need the framework's source repository to build your copy.

Voltfin 1.3.2 refreshes its BossMakerAPI dependency and is rebuilt against the 0.10.4 Contracts DLL. This does not change boss balance or rename or retune the encounter. Its reserved identities are example.howtofish.voltfin and example.my_pack.voltfin. Before distributing your own derived boss, choose new unique plugin/boss IDs, assembly and package names, an author identity and your own licensed icon. Keep the MIT notice. Do not publish an unchanged copy under a second package name: it would collide with this mod.

Compatibility, saves and support

The API's primary inspected target is 1.1.3/build 25604825. Exact 1.1.3/build 25603657, 1.1.2/build 25597996, 1.0.12 and 1.0.11 are retained references. On 2026-09-30, the release owner reported successful completion of the requested in-game checks with installed Voltfin 1.3.2 and API/Devourer of Light 0.10.4 on 1.1.3/build 25604825. This is owner-reported acceptance, not independent or exhaustive multiplayer, Steam Cloud or edge-case certification. All builds use exact assembly checks. An unknown update is not automatically supported. Share the same API/content builds across your session; matching version text alone is not a substitute for matching DLLs.

Voltfin opts into supported corpse and living-encounter persistence. Matching content is required; in-progress casts are cancelled rather than replayed. Native item eligibility and the 64-item cap still apply. Re-saving without BossMakerAPI can discard its metadata. See the API's docs/PERSISTENCE.md for the supported boundary; this is not a guarantee of Steam Cloud transfer or automatic migration from changed definitions.

Aquatic recovery is bounded collision-aware assistance, not pathfinding or corpse buoyancy. The native boss slot is shared with other bosses. Arbitrary UI mods, all coastlines and every third-party combination are not guaranteed.

For an issue, record game/build and API/Voltfin versions, host/client role, reproduction steps and a sanitized excerpt of BepInEx/LogOutput.log. Include the boss ID and relevant settings; do not share credentials or private paths. The companion API documentation includes troubleshooting and support guidance.

By SkyLiN3. Development used AI-assisted tools. The code is MIT licensed; native models, audio and other game assets remain in the player's own installation and are not redistributed here.