Destiny 2's The Witch Queen expansion saw a new faction of enemies introduced. The Lucent Brood, Light-wielding Hive, have been a significant thorn in the sides of Guardians since they were first encountered above Mars.
One such thorn is Mor'ak, Lightstealer. This Hive Lightbearer Acolyte Lieutenant leads hunting parties in the EDZ to kill Guardians and steal their light for Savathun/Immaru's dark experiments. It is the final boss at the end of the Psi Ops Battleground: EDZ activity.
How to defeat Mor'ak, Lightstealer in Destiny 2
Fighting Mor'ak is like taking on any other Hunter-based Lucent Brood. The key thing to watch out for is Blade Barrage as it can easily kill Guardians if several of the blades hit. You can tell the attack is charging up when you see several flaming blades appear above Mor'ak's head.
Each time Mor'ak loses a third of its health, it will teleport away and Guardians will be faced with an Aspect of Savathun. Use the Synaptic Spear to take her down. Once Savathun is dealt with, Mor'ak will return. Upon reaching the last third of its life, Mor'ak can be gunned down for good.
For more Destiny 2 goodies, check out New Playlist Weapons Coming to Destiny 2 in Season 17 on Pro Game Guides.