Light Must Shine
If you’ve been playing Destiny: The Taken King since launch, there is a good chance that you’ve already reached that coveted level 40. But, not to rain on your parade or anything, that is only half of the preparation you need to do in terms of guardian progression. Your level unlocks the option to play certain activities, but it’s your Light that determines if you’re able to complete the challenges.
Destiny: The Taken King takes a look at both your defense and attack as well as a few other parameters in order to set your Light Level. The King’s Fall raid requires that a player’s light be somewhere in the vicinity of 280 (that’s a lot of brightness). This is much easier said than done. But, if you take the time to not try and hold onto relics of the past (such as Year One legendary and exotics) you will have a much easier time.
Constantly switching to newer Blue or Purple gear will help you raise that Light rating in no time, this goes for your weapons, Ghost, and Class Items as well (three factors often overlooked). If all goes well, by the time you complete the main segments of The Taken King expansion, you should be somewhere around 220 (give or take a few). Now just run some strikes to both earn gear you want, and fodder for infusion. Completing questlines also unlocks some legendaries for free, so keep that in mind as well.