Haze can be a reasonable defensive pick even when Poison is not your main damage plan. Its beta rework lets one card pressure several enemies while weakening their attacks. The question is whether you can spare two Energy on the turn it appears.
Check the branch before building around it
The main-branch version and beta version are different cards in practical terms. Beta Haze is a two-cost Skill without Sly. It applies 4 Poison and 1 Weak to all enemies; the upgrade raises those values to 6 and 2.
That change came in v0.110. The later v0.111 notes did not change Haze again. If you are playing main, use the main text in the card reference, not the numbers in this beta guide.
What happens to the rest of your turn?
In an illustrative three-Energy hand, Haze leaves one Energy. Before playing it, ask what that remaining Energy can buy.
If one defensive card covers the reduced attack, Haze may solve both survival and future damage. If you need two other cards to survive, its combined effect may still be too expensive. Weak is not Block, and Poison does not automatically remove an attacker before its attack.
This is where Haze differs from simply adding another Poison card. Its value includes the attack reduction on the same turn, but that reduction must be relevant to the enemy's intent.
Haze or another defensive card?
Against several attacking enemies, the all-enemy application can save you from having to choose one target. Against a lone enemy preparing a non-damaging action, immediate Weak has less work to do.
Do not calculate Haze's value by multiplying one imagined saving across an entire fight. Enemy patterns change, enemies die, and later applications can overlap with Weak you already have. Compare the next dangerous turn you can actually see.
A hand that already contains enough Weak may prefer plain Block or a kill. A hand with no attack reduction may get much more from Haze.
When the upgrade deserves a campfire
The extra Weak duration can matter more than the extra Poison when Haze is your only dependable group debuff. It gives you a longer window to draw the next answer.
That does not make it the automatic first upgrade. If another upgrade fixes an Energy bottleneck or turns a near-kill into a kill, compare that immediate effect. The rest-versus-upgrade guide is useful when the campfire decision also involves low HP.
Connecting it to a Poison deck
Haze supplies Poison to multiple targets, but the rest of the deck still needs a way to turn that pressure into completed fights. The beta Outbreak guide covers immediate Poison activation. The Mirage guide explains the current defensive interaction and its Exhaust restriction.
Those cards do not have to appear together. Take Haze for a job your deck already needs, then use later rewards to improve the plan. Forcing the full package can leave you with several expensive cards and too little Energy to use them.