Status effects: damage, movement and support
Burning damages enemies but makes them move faster; Poisoned damages them while slowing them. Oil strengthens fire damage, while Stunned stops movement without stopping attacks. Those differences matter when choosing damage versus space to manoeuvre.
These are the developers’ dated pre-release descriptions, with current-demo support for the Nuln Oil/fire interaction. They do not establish that every listed effect appears in the October demo.
Pick the effect for the immediate problem
If the problem is a crowd closing in, Poisoned offers a slowing effect as well as damage. Burning can help wear down tougher enemies, but its faster movement calls for more space. These are deductions from the official behaviour descriptions, not a tested global damage ranking.
A stunned enemy is not harmless: the earlier official description explicitly leaves attacks active. Avoid standing in attack range simply because the enemy has stopped moving.
Keep Oil separate from the evolved weapon
Nuln Oil’s Hourglass pairing answers a different question from the base status interaction. The sources do not establish that Mordant Earth preserves every base effect, or that Hourglass itself boosts fire.
Champions and strengthening enemies
Status effects can affect the player too. The August reveal says the Frenzon pick-up grants the player Berserk, increasing attack frequency. An earlier May reveal uses Frenzied with a broader set of properties; that older list is not added to the later player buff here.
The September faction reveal describes enemy Synapse Berserk as increasing movement speed and damage. Destroying the strengthening source can temporarily stun nearby lesser Tyranids. Separately, Bell of Doom gives nearby Skaven Warded, making them more resilient. Read the enemy guide for responses to those sources.
The official reveals provide examples, not an exhaustive status list, immunity database, duration table or stacking formula. For what to do when a specific item appears, use the pick-up guide.