What it does
Dark-type moves hit 20% harder. No HP cost, no lock. Non-Dark moves get nothing.
Who runs it
Kingambit at 41% is the headline user. Its core move is Kowtow Cleave — a never-miss Dark physical move — backed by Supreme Overlord, which stacks Attack and Special Attack for each fainted ally. The longer the game goes and the more allies fall, the stronger Kingambit gets. Black Glasses amplifies every step of that escalating power curve by 20%.
Why not Life Orb? Kingambit enters mid-to-late game, often after one or two teammates have fainted (which is exactly when Supreme Overlord peaks). Life Orb recoil consumes the HP it needs for that comeback sweep. Choice Band is numerically stronger at ×1.5, but locking into one move prevents flexible use of Iron Head or Sucker Punch as situations demand.
Spiritomb at 6% concentrates its output on Dark and Ghost moves almost entirely. Hydreigon at 5% often prefers Life Orb but runs Black Glasses in more defensive builds.
How to use it
Timing Kingambit's entry matters. Send it in after at least one ally has fainted to activate Supreme Overlord immediately. From there, Kowtow Cleave ignores evasion and deals consistent damage every turn. Opponents who want to wall it need dedicated physical bulk, which usually means they have exploitable weaknesses elsewhere on your team.
Tips & strategy
Long games are where Black Glasses pulls ahead of Life Orb. By turn 5, Life Orb has cost 50% HP. Kingambit's window of influence shrinks accordingly. Black Glasses keeps that window open.
Sucker Punch is also Dark-type and benefits from Black Glasses. When a weakened target is about to attack, Sucker Punch with the 20% boost lowers the KO threshold — more situations where it can finish the job.