Remus is the twin sister of Romulus, and used to help her brother with his mission to gain as much power as possible. That was until Romulus Sabretooth Wolverine, and herself broke into the Weapon X facility and Wolverine volenteered for the Adamantium bonding process. She told her brother to stop or she'd walk away from everything they had done. He wouldn't stop so she left. Romulus then had Professor Thorton erase Wolverine's memories particularly the ones that involved Remus.
Remus was created by Jeph Loeb and Simone Bianchi and first appeared in Wolverine #310.
Mayor Story Arcs
Remus first appears during the battle between Romulus and Wolverine, and stabs Romulus with her sword from behind. She cautions Wolverine that her attack won't keep him down for long, and further warns him as he's about to pass out that he'd need to 'heal up.' Then in an interesting twist, she goes to kiss Wolverine as he passes out and also whispers something that's incomprehensible to the reader in his ear.
Remus later appears once again to aid Wolverine in the fight against the Sabretooth clones, remarking that he 'looks like hell.' Further flirting with him, she passes him one of her swords which Logan then uses to blow the facility up. As the two are escaping from the exploding building, Remus remarks that their ride is here and runs over to a descending helicopter. The two quickly board as the entire Weapon X complex is engulfed in fire.
Wolverine soon after remembers where else he heard her unusual accent before, and demands to know who she is. Remus reluctantly complies and imparts to Logan that she is Remus, the twin sister of Romulus. She then asks Wolverine a favor, and that is for him to kill her twin.
Wolverine doesn't believe what she is saying and throws them both out a helicopter but when they land wolverine notices Remus has the same healing factor. She then convinces Wolverine that Romulus is a threat that he will need her help to stop.
The two then find Cloak and use his teleport powers to sneak in to Romulus's fortress in Italy. There Remus stays with Cloak and Dagger while Wolverine runs off to face Sabertooth. Once Romulus gets in the fight that is when Remus show up and fights her brother. Sabertooth, realizing he is loosing goes to plan B, a bomb. Cloak teleports Remus and Dagger out of harms way.
Later, Remus is seen with Wolverine on a beach some where warm, the two are now in love. And Wolverine remembers the day he got his Adamantium and how Remus was there trying to talk Romulus out of it.