#you know how the dmc5 artbook or whatever said that the qliphoth gave dante a throne because it confused him for vergil

[mariyekos]

I like to think that Dante and Vergil are basically made up of four halves of the same two souls, mixed and matched to make two people.

The idea is that in the womb, both a human and demon soul tried to develop, but since one being couldn't contain two souls, it split into two, resulting in twins. Yet since the genetic material was also made of both sides, rather than one twin getting the human soul and the other getting the demon soul, instead the souls themselves split in two, with each twin getting half of one. One half demon, one half human. By the time Dante and Vergil were born, the two half-souls each twin had had merged into single souls, so essentially they each have one whole soul, but those souls are blends of two half souls and match each other at that.

It ends up creating some interesting effects. Blood magic is something that sometimes works for both members of a set of identical twins- being most effective closest to birth and often lessening in effectiveness with age- but there are also magicks which resonate with the soul instead, and thus don't work for identical twins, who normally have independent souls despite shared blood.

Except they do for Dante and Vergil. Because even though they're separate people and should have different souls, they register as being the same.

Because they are, in a way. Two base souls, four identical halves, two once-identical people. With pure humans, the soul doesn't develop until much later in gestation, long after the zygote has split in two. This means that human twins have separate souls despite shared blood. But add a demon into the mix and things get funky, the soul beginning to develop almost instantly after conception. And while Dante and Vergil may have diverged appearance-wise with age and differences in life experience, their souls stay the same. So soul magic which should only work on an individual level works on both, which can be both a boon and bane. It all depends on the context.

[This is perfect for both fluff (Vergil can get into Dante's locked rooms because the seals think he's Dante) and angst (a spell meant to trap one either successfully traps the other, or manages to get both, pleasantly surprising the one who set it and proving bad for our protagonists who mean to fight them). Context!]