This is how to get Destiny 2's Exotic sidearm, Rat King
One rat by itself is no issue. But a swarm of rats all attacking at once can be deadly.
This is the thought process and the general idea behind Destiny 2's Exotic sidearm, Rat King. The gun actually becomes stronger when nearby fireteam members are also using the gun, making it deadly when your squad rolls deep with it.
Here's how to join the rat pack with your own Rat King.
Weapon Trait - Rat Pack: If nearby fireteam members also have Rat King equipped, it becomes more powerful. This effect stacks up to six times.
Smallbore: Increased stability, increased range.
Tactical Mag: Increased stability, increased reload speed, increased magazine size
Smooth Grip: Increased stability, increased handling speed.
Bonus Trait - Vermin: A brief period of invisibility is granted when reloading immediately after a kill.
Rat King Quest
Once you finish the game's campaign, head to Titan and speak to Sloane. She will give you a quest called "Enemy of my Enemy." Once you finish it, she will reward you with an item called "Rat King's Crew" which will take up a slot in your Kinetic weapon inventory.
This quest is a series of riddles, but they're not as difficult as they may seem. Each riddle is solved by finishing a series of simple tasks.
First riddle: Complete three Patrol missions. Patrol missions are found scattered around the open world in the end-game, and are marked by poles with blinking lights. Pick up any three and finish them.
Second riddle: Complete two Public Events. This one is pretty easy. Just wait for Public Events to pop up in any location and finish them. They don't need to be Heroic versions.
Third riddle: Complete two matches in the Crucible. Again, very simple. Just play two PvP matches. You don't even need to win them.
The final riddle: Complete the Nightfall Strike with at least five minutes remaining. This one is difficult and can be extremely tricky. Odds are that this one will take a number of tries to get down right, as Nightfall Strikes are difficult until you've mastered the Strike itself.
Killing enemies adds to your time, so try to clear out as many adds as you can while moving through that week's Nightfall as fast as possible. Keep trying until you get it done. Once you do, the Rat King is all yours.