Blizzard has just revealed the upcoming Season of the Construct. One of the new mechanics in Season 3 will be acquiring your own customizable Seneschal Companion!
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The Seneschal Companion can be acquired during the new Zoltun Kulle seasonal questline.
This companion will fight by your side until Season of the Construct ends. The Seneschal can be customized through the use of Governing and Tuning Stones.
Completing a Vault will reward you with one random Tuning Stone.
Players also have a low chance to find Governing Stones and Tuning Stones when playing Vaults and Arcane Tremors. Wardwoven Chests, earned through various levels of the Season Journey, also yield additional Governing Stones and Tuning Stones.
Governing Stones and Tuning Stones can also be crafted at the Jeweler with Shattered Stone, which can drop from the new Construct monster family within the Vaults.
Players will have to level these Governing and Tuning Stones to increase the potency and ability of their attacks. This can be done by collecting or crafting duplicates of the same stones and fusing them to grant experience and level them up.