Meryll Strife aka Derringer Meryll: She, along with Millie Thompson, are employees of the "Berunaruderi" insurance organization. She has been assigned to keep Vash out of trouble. Early on in the series Meryll and Millie attach themselves to Vash. They follow him wherever he goes in an attempt to prevent disaster before it strikes, hoping that their insurance company does not have to keep paying out settlements. She is extremely strong-willed and persistent. Her nickname comes from hiding dozens of derringer pistols in her outer cloak which she can draw and fire very quickly and very accurately.

Millie Thompson aka Stun-gun Millie: Millie is extremely large and strong but also extremely nice, naive, happy and trusting. She grew up in a large family with many other siblings and she constantly writes huge missives to them. She looks up to Meryll-senpai. Her nickname comes from the "stun gun" that she wields; it shoots large stunning (via impact) rods that snap out when shot from the gun.

Nicholas D. Wolfwood: A somewhat mysterious person who seems to be a preacher. He carries a large cross wraped in cloth and tied up with belts. In reality, this cross is a miniature arsenal that opens up nicely when unwrapped: the arms being laden with pistols that fold out on need, the long end is a rather powerful machine gun, and the short end is a grenade launcher. He ends up traveling with Vash. As time goes on, we realize that he has a hidden agenda. Although he attempts to do good as Vash does—helping people out in situations that no one else will volunteer for—he is unlike Vash in that he will kill if he feels that he has to. This becomes an important element of their relationship.

Millions Knives: Like Vash, he is related more to the Plants that people use for power than to humans. Also like Vash he was raised by Rem. Unlike Vash, however, his love for Rem did not shield him from his nature and his belief that he was just a tool, a machine, a weapon created by the humans to protect the colony. He resented the implication that he was to be a servant of these inferior humans. Shabby treatment by some of the SEEDS crew further fueled his resentment. Rem's efforts to treat Knives with love so that he would love the people and protect them of his own free will ended up in failure, as Knives sabotaged the SEEDS as they neared the planet. Knives is still after Vash because they are of the same blood, so to speak. His efforts with the Gung-ho-Guns to turn Vash is reminiscent of the Emperor's attempts in STAR WARS to turn Luke to the Dark Side.

Legato Bluesummers: The most powerful of the Gung-ho-Guns. Not only can he control people with thought, but he cares nothing for them. His spirit is twisted and capricious. He keeps the other Gung-ho-Guns in line as viciously as he kills innocent bystanders. However, this is all done with an extremely casual regard, as if all life were inconsequential, even his own. His one goal is to drive Vash to the edge of despair and beyond, and thus turn him bit by bit to Knives.

Rem Seiburem: If there is one person who has defined Vash's life, it is Rem. She pretty much raised Vash and Knives from when they were born. This was despite some of the SEEDS crew thinking that they did not deserve to be treated like humans with so much care and understanding. Vash fell in love with her very early on, and her loss is what shaped his present character. Vash learned the value of life when witnessing Rem sacrifice herself: Rem refused to abandon the SEEDS ships so that she could save some of the colonists.