Jesse (Buffy)
From Multiversal Omnipedia
Jesse was the best friend of Xander Harris and Willow Rosenberg by the time they were sophomores at Sunnydale High School. He was among Buffy Summers' first friends when she arrived in Sunnydale, but was soon turned into a vampire by the Master.
As a vampire, Jesse led his former friends into a trap, and later was among those who attacked the Bronze under the command of the Master's lieutenant Luke. Xander wound up threatening his undead best friend with a stake, and accidentally slew him when Jesse was bumped into the stake by a scared Bronze-goer.