All planets contain a secret exotic weapon that can be obtained after you complete all of the missions and quests on a single planet. You will not be able to complete everything on your first visit. Often you will find you need to progress and complete the story before coming back to complete new quests that have appeared since. However, it is best to try and do as much as you can, while you can rather than rushing through the game. There is a hell of a lot to see outside of the main story.
This video guide will show you how to get rat kings crew exotic weapon from Titan. Below is a brief description on what you need to do to get this. People are reporting that they have been unable to complete the requirements solo and some have found issues even while in a fire team. It is not confirmed what the minimum requirements are, but you must have a fireteam and everyone must be taking part for this to count. I will update this guide once i find out more and if anyone has the answer, please leave a comment below.
Rat Pack: This weapon becomes stronger when nearby fireteam members also have it equipped. Stacks up to 6 times Vermin: Reloading immediately after a kill grants a brief period of invisibility.
- Complete all of the quests on Titan. The quests are marked by the blue icons with a crown icon inside of them. Some people do report issues with these not showing up if you progress past them. It may be a glitch, but for now it is wise to do the missions when they show up.
- Complete 3 patrol missions. You will find a blue quest on the left of the EDZ on earth that will unlock the patrols.
- Complete 2 public events
- Win 2 crucible matches.
- Complete Nightfall with at least 5 minutes left on the timer.