The Immortal

The Immortal is an old rival of Angel and Spike, an extremely respected and admired being serving no side but his own desires. He has accomplished numerous incredible feats and managed to seduce many women, including Darla, Drusilla and, supposedly, Buffy Summers, though this was merely a decoy.

Accomplishments
According to various people that know the Immortal, he has accomplished the following:
 * Spending 150 years in a Tibetan Monastery
 * Climbing Mount Everest several times.
 * Dealing with the Italian Branch of Wolfram and Hart several times and surviving. (The female CEO of the Italian Wolfram and Hart, Ilona Costa Bianchi may have been referring to business dealings or a more personal encounter, quite possibly both)
 * "Violating" Drusilla and Darla, not only both of them but both of them at the same time. Something that neither Spike nor Angel could get either girl to agree to.