Synod
The Synod were the ruling council of the Keepers of Terris. They were present both before and during the Lord Ruler's reign, but it is yet unknown if they continue to rule the Terris communities in the Alloy of Law.
The Synod charged themselves with keeping knowledge of the world before the Lord Ruler's ascension. However, they did not openly rebel against the Final Empire, instead staying as a secret organisation based in Tathingdwen, in the Terris dominance. The Synod opposed Sazed's decision to assist in Kelsier's rebellion.
After the Lord Ruler's death, the Synod spread the knowledge collected from before the Ascension. Tindwyl, a keeper of the Synod, travelled to Luthadel to assist Elend Venture in securing his kingdom's borders.
In the later events of the Well of Ascension, steel inquisitors attacked the Tathingdwen under the influence of Ruin, killing all of the Synod in the city. This left Sazed as the only known living Keeper.