Maliwan's Torment use Jakobs's pistol barrel, which grants it high damage and precision.
As with all pistols that use the Jakobs's long barrel, the Torment only comes in green rarity or higher.
The Torment is obtained randomly from any suitable loot source.
Maliwan's Torment is, regarding gun colour (White, green blue, etc...), very uncommon in comparison to other pistols.
Pistols that have the Jakobs barrel (Ass Beeter!, Peacemaker, Leverage, Iron, Torment, Power Shot, Rod and Fighter) will be displayed smaller when carried by Zer0 while in status or quick change menus, more than it usually has to be.