Man, emotional depth in Elphaba/Glinda fics... that's tricky, because a lot of them can slip into either pure fluffy romance or just retreading the musical's beats. For a truly gut-wrenching, emotionally layered take, 'The Gravity of Birds' by LyraLinn is my top recommendation. It's a post-canon epistolary story, all letters and diary entries, and it absolutely nails Elphaba's voice—that blend of sharp, wounded intellect and hidden tenderness. Glinda's growth from the socialite to a quietly grieving, politically savvy stateswoman feels earned and painful. The emotional depth comes from the unsaid things between the lines, the decades of regret and love that can never fully be spoken because of who they are and what happened.
A different angle, more about the emotional depth of the connection rather than the tragedy, is 'Til the Sun Grows Cold' by ambyr. It's an AU where Elphaba never gets melted, and they navigate a secret relationship in the Emerald City. The depth here is in the small, terrifying intimacies: Glinda learning to touch someone who flinches, Elphaba allowing herself to be cared for. It’s less about grand tragedy and more about the exhausting, beautiful work of building trust when the world is against you. The author really gets into the psychological weight of Elphaba's skin, not as a metaphor but as a daily reality that shapes every interaction.
If you want something that absolutely destroys you, look for 'A Tendency to Fall' which explores a 'what if' scenario where Fiyero dies earlier and the two women are left to pick up the pieces together. It’ s raw, full of grief and guilt, and the slow transformation of that shared pain into something like love is brutally well-done. It doesn't offer easy comfort, which is why the emotional punches land so hard. The ending always leaves me staring at the ceiling.