A time to rend, and a time to sew; a time to keep silence, and a time to speak

William Blake. A crisis bears witnessing

When the world was being formed and focused, God required witnesses to look over the mortals to come. So was placed the city of Gath, perched on an island over the deepest lake in the world. So were made the dwarves of Gath, who see for God.

They have been made to last until the end of the Earth, and their hairs are starting to grey. Mostly they stay in Gath, sending out individuals to witness important events. Almost every battle in the history of Selmat was fought within sight of Gath so that God may see it, and by this point the lake is surrounded by ruins and corpses. It is said that they make iron weapons from the blood of those centuries of slain, and it is true. Within the city, the dwarves mostly just tell each other stories so that they may be remembered forever. For fun, they also like to share satires of centuries-old events

Hubert Robert. Out of the View of God

The Biritists of Selmat honor the dwarves, and to see one is more rare than to see an angel. Kings send messengers to Gath to request the presence of a dwarf for historic events, and these requests are often granted. Noryists, fearful of the pantheon from which their god was exiled, are likewise fearful of dwarves.

This is perhaps wise.

Karl Kopinski

Witnesses

Witnesses are like bards but less musical. They use wisdom instead of charisma for all the "bard" stuff, and their performances are states of perfect recall triggered by the crush of history. 

Witnesses get +1 to knowledge skills for every fifteen years they've been alive. This is somewhat impressive for PCs, but makes knowledge checks auto-successes for dwarf witnesses, since they are as old as the world itself. (Dwarves are not a PC race in Holy Selmat.)

Smart players will note that they have perfect recall of events that take place while doing a witness performance, and perform during events that they want to remember, which I think makes a lot of sense. One of the books I read in anticipation of running Holy Selmat was Green Ronin's TESTAMENT, which included the psalmist class in a similar niche to the witness. This one is a bit less bardy that the psalmist, and a bit less... specific?