The Abbot is the highest leader of the History Monks (the Men in Saffron) in the Oi Dong (No-Such) monastery. This Abbot should not be confused with the Abbot of the Listening Monks mentioned in Mort.
It appears the Abbot hasn't mastered the art of circular aging used by the monks, so he has to use re-incarnation. This means that every few decades he is reborn, but he keeps his centuries-old mind capable of thinking in 16 dimensions. Is presumably the same as the 493rd Abbot (he of the wrinkled hands) encountered in Small Gods dispatching Lu-Tze to Omnia. Obvious Roundworld counterpart: the Dalai Lama.
A genius of no short order, he was once seen playing a game of chess against Death. And seemingly winning as he was the only one of the two who had an inkling 'how the little horse-shaped ones move .'
Credited (by Lu-Tze) with figuring out how the Yeti 'saved' their lives up to a certain point and then blithely approached potentially dangerous situations confident in the knowledge that if they were to end in serious peril they could return to a previous point with prememberance (to quote Lobsang Ludd before he became the avatarian incarnation of Time) of what would happen if they followed the same course. This is, of course, a sly nod at certain computer games where exactly this is de rigeur if players are uncertain or low on life approaching an unknown door. Also credited with creating words such as Yonk and Oodleplex to confuse novices.
Found in Thief of Time as a toddler, being in the very early stages of his latest incarnation. This leads to embarrassment all round when he is breast-feeding... Struggles with maintaining erudition in his speech, as mumbles and baby-talk creep in.
Has an irritating, smug and petty-minded Chief Acolyte named Rinpo, who has a known dislike of disorder, disobedience and Lu-Tze. With seeming child-like simplicity and innocence the Abbot keeps 'accidentally' whacking Rinpo with a wooden toy or upending sloppy food down his robes.
Accorded the highest honour when Lobsang (as the incarnate Lord of Time) bowed before him at Oi Dong.
The Abbot is also the official title of Doctor Whiteface at the Fools' Guild. The reason for this is that the Guild of Fools explicitly views itself as a closed monastic order seeking purity through devotion to the Great Work, untrammeled by mundane things like soft beds, more than minimal rest, contact with women, and other sullying influences. Below him are Obedientaries (Guild officers with an administrative function) and the Cloistered Priors (the treaching staff of the Guild School). More details may be found in Discworld Fools' Guild Yearbook and Diary 2001.