Blindness

Blindness is not a retest like brawl or Willpower is. In a situation where your character is blind, you suffer -2 traits on all challenges that involve sight or awareness, but do not require it (attacking, Falling Touch and resisting Clap of Thunder are at -2 traits, Stare Down and True Fear fail, Rage Healing and Jam Technology suffer no penalty). Resolve the challenge as normal. If you have won, you must throw one more time to see if you missed from not being able to see your target. The only valid cancels are: Blind Fighting, Pack Tactics (only if your plan involved fighting in the dark or being blind in a manner you and your pack control*), Luck, Oracular Ability, Desperate Strength.

*Planning for similar conditions will still be valid. If your Uktena decides they will create darkness as part of the plan but you happen to be fighting a vampire that drops Shroud of Night first, the conditions and style of darkness is similar enough to what you were planning for that it won't surprise you and you may use Pack Tactics. However if you were planning to be fighting in a well-lit room and suddenly everything goes dark, either because your Uktena didn't communicate, you came across a Lasombra, maybe there's just no windows and the power went out, you may not use Pack Tactics.