Duel in the Guardian's crypt

The Duel in the Guardian's Crypt was a fight between the Slayer Buffy Summers and the First's minion Caleb with Angel assisting Buffy.

Background
After finding the Scythe, Buffy travels to the Guardian's Crypt to find answers about the Scythe. There, Buffy encounters the last remaning Guardian who fills her in on the history of the scythe. After explaning its purpose, her neck is snapped by Caleb who taunts Buffy before engaging her in a fight.

The First Round
Buffy and Caleb engage in a fight to the death against each other, but due to merging with The First recently, Caleb is more powerful than ever and Buffy has to struggle just to keep up. Buffy proves to be no match for Caleb though she does land a few blows and is knocked down with Caleb ready to kill her with the Scythe when Angel suddenly joins the fight. Angel knocks Caleb out for a moment, saving Buffy from death and allowing Buffy a moment to recover her strength.

The Second Round
Caleb recovers fast and Angel tries to help Buffy, but Buffy has Angel just watch as she wants to fight Caleb alone. Caleb and Buffy fight each other again and this time their more evenly matched even though Caleb is still the stronger of the two. Finally Buffy manages to duck one of Caleb's blows and slices him across the stomach, apparently killing him with Angel, The First and Spike watching.

The Third Round
After everything seems to be over, Caleb rises again and knocks Angel out, his incredible power from his recent merge with the First allowing him to survive his wound for at least a time. Caleb engages Buffy again one on one and while he is still incredibly strong and powerful, his wound also seems to have weakened him a bit, giving Buffy more of a chance. Finally, Buffy manages to knock Caleb to the ground and when he gets up again, swings the Scythe up into his crotch while he's taunting her. Buffy then pulls the Scythe all the way up through Caleb, cutting him in half and finally killing him.

Aftermath
After Caleb's death, Angel gives Buffy an amulet and file on the First he got from Wolfram and Hart before returning to Los Angeles at Buffy's insistance. Buffy ends up giving Spike the amulet and the First appears to Buffy that night in the form of Caleb to taunt her. The First confirms Buffy did in fact kill Caleb in this fight and tries to demoralize her, but instead, the First's taunting gives Buffy the plan to turn all of the Potential Slayers into Slayers to battle the First and its army.