#livio and the other orphan children were more of a guinea pig for what nai wanted to do to vash

[brotherslayer]

lots of things can be read into Vash bonding with Wolfwood (older brother) and Nai's cult kidnapping and brainwashing younger children into total obedience (Wolfwood's younger brother) and Vash seeking out the company of humans who resemble his foster mother Rem Saverem and are characterized by a loving and nurturing personality. Vash likes motherly women (Rollo's mother, the mother in the first episode) and black haired humans whose most defining character traits are pacifism, idealism, compassion, protection and self-sacrifice (Luida, Meryl, Wolfwood) all traits that can be found in Rem. Wolfwood is what Vash wishes his brother was: someone still redeemable. A strong older brother who is protective of his younger siblings, someone who deeply cares and doesn't try to mask his violence as love. Livio is what ep 11/12 Nai wishes his brother was: an empty husk that only lives to realize Nai's ideals and does what he tells him to do without questioning anything. Even after living over hundred years apart from each other, they are still looking in others for some kind of replacement for the family they've lost.