Mara Venn
Original campaign-world reference. Sections describing the supplied Day 17 instance record that playthrough only; possibilities remain possibilities.
Role: Taren's sister and a person connected to Edren's older history. World lore: She may possess an entrusted component or information; the creation helper frames this as a possible feature, not a fixed fact in every instance. Her knowledge should remain partial and distinct from Merrick's, Taren's, or Calder's.
Day 17 instance: Mara carried a component from the first Warforged, and the First Sentry was reawakened with Mara's component. The source does not say where Mara is now, whether she still possesses that component, or that reawakening gives anyone ownership over her or the construct. Her surname does not establish identity or family relation with Mara Vale from the earlier adaptation.
Sources: creation helper, Vale/Taren/Mara/Calder; campaign continuum, important NPCs; campaign continuum, First Sentry.