I've noticed that in the opening sequence, and the big climactic moment at the very end of the season, Lucy has her hands on the figure's back with the ring/middle fingers together and the other two fingers separated in a 'w' sort of shape.
Is this a symbol of love, a reference to Gustav Klimt (like the paintings) or something else?
I've also noticed it on the cover of the 3rd Vampire Bund Omnibus.
The hand gesture is a secret sign indicating that the gentleman is a Marrano -- a crypto-Jew who accepted Christian baptism in order to remain in Spain after the Catholic Kings' order of 1492 that all Jews leave Spain;
The gesture indicates a Loyolan/Jesuit spirituality that calls for the sinner to place his/her hand on their chest after committing a sin as a sign of moral pain. Both of these theories have been discussed at length in academic circles without, however, formal acceptance of either, though at least one academic allows that the hand "assumes the function of an important communication, a personal avowal."
It has been suggested the M symbol of the fingers refers to Mary Magdalene and the theory that they had a child. Knights Templar order and all that. Famous portrait (posthumous) of Christopher Columbus shows his fingers in this arrangement, various statues and paintings also show hands arranged this way. It's rather curious as it's not a natural way to hold your fingers. Some people say the Statue of Liberty, the hand holding the tablet also shows this arrangement. The Freemasons were involved in many of these things and it's said they are what remains of the Templars.
The hand gesture Lucy makes in official art and during the opening is prevalent in Loyolan/Jesuit spirituality, wherein those who commit sins are to place their hands on their chest with the middle and ring fingers joined to show moral pain and/or remorse for their actions.