Darklighter Crossbows are the main weapon used by Darklighters to kill their good counterparts, Whitelighters. The arrows of the crossbow are dipped into a lethal poison, which is one of the few things capable of killing Whitelighters, Whitelighter-Witches and the Elders.
Darklighters summon their crossbow to their hands through Apportation. The crossbow appears and disappears in a puff of black smoke.
A Darklighter Crossbow was first seen used by Alec. He used it to shoot Leo Wyatt when he was protecting his charge Daisy. He later tried to shoot Prue and Phoebe Halliwell with it. Phoebe threw him with her temporary power of Telekinesis, and he dropped his crossbow. Prue picked it up and almost shot Alec with it, but he orbed out in time.
The following year, the Charmed Ones faced a warlock named Eames. Part of his plans to invade the Heavens, was obtaining a Darklighter Crossbow. He used it to kill the Whitelighter Natalie and stole her powers. He then orbed to the Heavens to kill all Whitelighters and Elders. However, the Charmed Ones stopped his attack and vanquished him before he could.
When the Charmed Ones faced the Source of All Evil, he sent a Darklighter to kill Leo so he could not protect or assist the sisters. The Darklighter succeeded in shooting Leo, though he was later healed by Paige.
When the Siren appeared in San Francisco, Paige suspected a Darklighter was involved and captured one with the Crystal Cage. However, the Darklighter managed to get out and immediately summoned his crossbow. Before he could shoot, Paige orbed his crossbow to her and vanquished him by shooting him with his own weapon.
Many Darklighters were shown, all of them holding crossbows. It is also shown in this episode that Darklighter crossbows have scopes.
The day Chris was born, Phoebe and Paige go to an alternate universe and meet their evil selves. They end up in a fight, in which evil Paige conjures a crossbow. She begins shooting the real Paige but Paige is able to orb every single arrow away.