Some theories: 1) Maribel becomes Yukari: At some point in the future Maribel returns to the past, gets stuck there and goes full youkai. This theory is very popular in www.shrinemaiden.org, being well defended there by Tiamat.
2) Yukari becomes Maribel: Yukari sees the magic dying and seals herself in a human to endure.
3) Maribel is a descendant of Yukari: At some point Yukari had children (with Lafcadio Hearn?) and Maribel descends from that union.
4) They're the same being but in paralel universes
5) Maribel becomes Yukari, who becomes Maribel (stable time loop)
FinderX said: this is little off but, nobody think Renko is somewhat similar to Reimu? mmm may be I only one think that way
no I've always thought that too, particularly with Renko's rather distinctive ribbons woven into her skirt and shirt, which up until more recently were distinct design elements only really elsewise present in Reimu's design.
myself, I've come to pretty much think of Maribel and Renko as doppelgangers of Yukari and Reimu, with all the lore that being doppelgangers implies
Read Trojan Green Asteroid. The hints are all but hitting you in the face that they're one & the same.
Going by cf's list, they're either 1, 4, or 5. Can't be 2 considering that Yukari is present at the same time Maribel is around. Can't be 3 considering that in TGA, Maribel can Gap exactly like Yukari does, and ZUN's own words is that Yukari's powers are 'only one of it's kind'.
