Several analyses of Shinji Ikari's character compare him to Yesod.
Now Wikipedia has this on Yesod:
Yesod (Hebrew: יסוד "foundation") is a sephirah in the kabbalistic Tree of Life. Yesod is the sephirah below Hod and Netzach, and above Malkuth (the kingdom). It can be seen as the vehicle, from one thing or condition to another (the power of connection).
I read some more on that, and I really didn't get it.
What is this connection / what traits does Shinji have in common with this sephirah? What symbolism does the MC of Eva have, in this context? Is it intended by the canon, or is it just an interpretation of the material?