Gang

In order from Back (left to right) Giles, Angel, Xander, Cordelia, Buffy, Willow and Oz.

They all help Buffy in her fight against evil in their own way, although you may think angel help her because hes half vampire and stronger than any of Buffy's friends put together, but They all contribute.
Willow is the wiccan of the group she's like a witch who deals with spells to disable the enemies tempararely, and who is also Buffy's best friend. Oz is a the Guitarist a Band who plays regularly at the Bronze they met at a school convention and fell in love instantly, he also has a secret which the group share he's also a werewolf, and he mainly hangs with the group cos willows his girlfriend.
Xander's another one of Buffy's good friends, who has always looked out for her , and saved her life on numerous occasions. Xanders always had a soft spot for Buffy and had let her know that he likes her, but Buffy depends more on the friendship, but he is always reliable although as many may seem him as some geek that hangs with Buffy. Cordelia is the perfect High-School Prom queen student who relis on her popularity to succed, although her attitude and putting people down is just so that she looks better thats Cordelia all over, she helps with the research work some of the time when shes not opening her mouth.

Rupert Giles is Buffy's watcher, the person who is chosen by the council capible of training and to be responsible for Buffy in everyway. Giles is more of a Father figure to Buffy than a Watcher, Boss or Teacher whichever was you want it, and i think personally that he see's her as a daughter too , as he has no children himself.
He is also the librarian at SunnyDale High School, and uses the books and title to his advantage, the group uses the library as a room where they scheme theyre plans. Giles can also speak 4 languages including latin, which always comes up because of the ancient demons.
Giles has never been married and lost his only love Jenni Calendar to the hands of Angelus who killed her and taunted him with his personal humour.
Giles was also a bit of a rebel in his day being called 'Ripper' Giles was given a reputation of being a bot of a tough guy, and within his group they experiemented in mischeif with evil and has some bad memories of bad moments.
Later when the Coucil sacked Giles form being watcher he was replaced by wesley, but Giles never gave up helping Buffy for one minute.