[tvongaza]

Problem

A level-3 Seal ragdoll can run LevelEffects.SetupLevelVisualization without a Character or ZNetView. If another mod has registered a custom creature, Jötunn's global cumulative-effects postfix dereferences that missing view and interrupts the Seal's death sequence. See #494.

Change

Return from the cumulative-effects postfix when LevelEffects, its Character, or its ZNetView is absent. Valid custom creatures keep the existing level-3+ behavior.

Validation

• Built JotunnLib and JotunnTests Release against Valheim 1.0.16 assemblies; 28 JotunnTests passed under Mono.
• Ran an automated pinned native A/B check in Valheim 1.0.16 with RtDOcean 2.2.49. A ValheimTesting SystemTest owned client hosted the same disposable fixture world in each arm, spawned one frozen level-3 Seal, confirmed its ZDO existed, and dealt lethal damage through Character.Damage.
• Unfixed parent f4bb471: the original Seal ZDO remained after 15 seconds, and Unity logged a NullReferenceException in CreatureManager.EnableCumulativeLevelEffects from Character.OnDeath.
• This fix fac8bd4: the original Seal ZDO disappeared on the first post-damage census; the hosted-world test passed and the client quit cleanly. The Jötunn DLL was the only A/B change.

Runner source and a build/run recipe are published separately (Program.cs, project file, README). The source contains no fixture, game binaries or private logs. The package-only example builds against Valheim.Testing.Game preview.15. The native A/B used the same scenario logic with a local project reference and two extra absent-plugin pins for station isolation; the public example omits those unrelated checks and has not been rerun in game. Reproducing the run requires a disposable Valheim 1.0.16 fixture and our pinned ValheimCLI fork, as detailed there.

This checks the reported Seal death/cleanup path. It does not assert loot distribution or every custom-creature death path.