This weapon is obtained from a quest line completed throughout the system. This is a Solar damage Side Arm equipped in the energy weapon slot. This weapon's perk is called "Close the Gap." This weapon perk allows the weapon to fire normal Side Arm rounds when you tap the trigger, although if you hold the trigger, this will fire a beam that melts most anything in its path. Should you want help in attaining this weapon, the Destiny Boosting team is here to help.
Start this quest by completing a run in the Sundial. Upon completion, you will receive the start of the quest in the reward screen at the rewards console.
Speak to Saint 14 in the tower. He will send you on a quest to the Twilight Gap Crucible map.
You must locate the dead Crucible robots and scan each one. Once complete, you will be rewarded with the Devil's Ruin.