Bianca

Varric has a signature crossbow named Bianca. Bianca possesses a carved-wood stock and brass embellishments; and for melee purposes, a retractable bayonet slides out of a slot under the bolt.

Background
When asked about the story behind how Bianca got her name, he replies that it involves a girl and a promise, and that it is the one story that he can never tell. He has put the story to song, but will not sing it, instead humming the tune during battle.

Upgrades
While Bianca is the only weapon Varric can use ingame, it is nothing to laugh at — it is one of the few weapons that level up with its owner. So, the higher level Varric is, the stronger this crossbow becomes.

Trivia

 * Bianca is called as such "because Mirabelle was taken". This is a reference to BioWare's Jade Empire, in which a powerful musket called Mirabelle can be acquired.
 * From a real-world perspective, Bianca is named after a young woman looking for true love in "The Taming of the Shrew" by Shakespeare.
 * There is a longbow with the Absolution model named Bianca in game files (item code gen_im_wep_rog_arc_lore_03).
 * Bianca is the only usable crossbow in Dragon Age II.
 * It was made by Gerav who tried to design a repeating crossbow. Bianca is the only one that worked.
 * Using console commands to add another Bianca to the game for any other companion besides Varric results in a non-appearing weapon for its user.