WOLVERINE #55-57 (1992): Wolverine kills Mariko

Wolverine is stopped at an airport metal detector.

Then: Jubilee is being held in a Japanese prison (women’s prison comic!), and Gambit and Wolverine head over there to help.  All the expected faces appear: Sunfire, Yuriko, Hydra, Silver Samurai, The Hand, and Wolverine reconnects with his old love Mariko.  She’s still trying to take her father’s crime business legit, and in the process she gets poisoned by Matsuo, the Hand ninja.

Wolverine kills her so she doesn’t suffer (it happens off panel).

From this point on, every year on the anniversary of her death, Wolverine swears he will cut Matsuo into pieces. He doesn’t, though. His death comes at the hands of Psylocke, after Matsuo was responsible for the body-switching that made her character so damn confusing.