Twice-Born Star is a craftable set available in all armor types. The 5-piece set bonus allows you to have two Mundus Stone Boons
at the same time.
Twice-Born Star is part of the base game. The crafting station is located in Craglorn (Atelier of the Twice-Born Star). You can craft any armor, weapon or jewelry of this set in any motif style you know, as long as you have 9 traits researched (per item). You can trade crafted pieces to other players. Each set item becomes bound on equip.
You can learn more about Mundus Stones in the Mundus Stone Overview Page