My mind slips into a Mage(the Ascension) mindset very easily. I see a concept that someone else created or reviled a new aspect about the concept, and I think how does that fit into a World of Darkness setting. I know to non-gamers it sounds geeky.
I started watching a new anime, Futakoi Alternative, and it has a underlying premise that the town were it is set produces a unnatural number of identical twins. From the short amount of the show I have watched (3 episodes of 13) I think that the twins are not in fact different people but opposing halves of the same soul. Now that is not all the interesting a concept, some twins may feel that way but it becomes interesting to me in the context of Mage the Ascension. I run the setting were avatars reincarnate. now if an avatar was to become attached to the soul of the identical twins, may would share it. That leads off in many interesting directions.
Other thoughts, Ian played a character whose avatar was his (or her,I don't recall) twin. In Bernard Cornwell's book The Pale Horse the character Iseult is said to have a connection to the underworld through her still-born fraternal twin brother. These are many thought I had about this topic that I wanted to record. engaged
The sharing of an avatar may confuse might lead to confusing consequences. or if you took the shattered avatar flaw you could only each advance until a one of you gave your power to the other or killed the other....... Hmmm. Reading through the mage specific merits and flaws gives me many way that this concept could be used.