kindsephirah
divine nameShaddai El Chai (שדי אל חי) — Almighty Living God
archangelgabriel
heavenly sphereLevanah — the Moon
in the bodyThe generative organ; the covenant
soul levelRuach (register: bonding, transmission)
The channel. Everything the upper Tree has gathered funnels through Yesod into Malkhut — it is the foundation not because it is lowest but because transmission is everything. The Moon: it makes no light of its own and delivers all of it. Sphere of dreams, images, the unconscious, sexuality as covenant. The tzaddik, says Proverbs, is the foundation of the world: the one through whom blessing actually flows rather than pools.
The Zohar's covenant theology lives here: Yesod is the river that goes out of Eden (Genesis 2:10), the flow that makes the union of the Holy One and Shekhinah possible.