How to defeat Eramis in Destiny 2

 The ultimate enemy in Destiny 2 "Beyond Light" is a female warrior named Eramis.  If you are working through the campaign, eventually you will be given the task to hunt down and defeat Eramis.  Fight your way through typical scenes until you get to her throne room...then the battle begins in two phases.  I'm not into all the Destiny 2 lingo and lore so you may have to translate a little.  But if you follow this simple procedure and are a slightly above average player you should be able to defeat Eramis without much trouble.  Most players use speed, luck, shooting skill and lots of tries to win this level.  I use cunning.  Brains wins over brawn.

Eramis

Phase One:  You will first discover Eramis in her throne room.  When you enter, the battle begins and she will summon lots of goons to take you down while she shoots at your with her freezing stasis blast.  There are lots of small objects to run and hide behind, none of them very good. Do your best hiding as you fight off wave after wave of goons.  In between each wave take some shots at Eramis.  When you finally wear her down a litttle, she will freeze you, disable your ghost, steal your shard, and give you a lecture.  Then she will depart to the outside decks.  This phase is not too hard, but there is no big secret to it.  Tough it out.

Phase Two:  When you go outside, you will see Eramis on a round deck with one smaller deck on each side.  All around them is a long fall into the abyss and certain death.  When you exit the throne room a shield descends behind you so you cannot go back.  You must face the enemy.  Notice that there is on semi-circular railing around the deck on which your are standing.  You have time to look it over.  Take a close look at the two extreme corners of the deck.  If you crouch in either corner, you are protected pretty good from the enemy.  Eramis cannot get a direct shot at you because of the railing, but the goons can still rush at you.  You have time for one stasis shot at her and then the battle begins.  Run immediately to one of the deck corners, crouch low against the railing, and wait for the 1st wave of goons.  Shoot them with whatever you like but remain crouched down because Eramis will be trying to hit you with stasis.  

Wave after wave of goons, and shanks will come.  Just keep blasting them.  In between each wave, stand up and take one or two quick stasis shots at Eramis (it is your new super power).  Use the faint sighting ring to aim your shots.  Duck down and wait for the next wave of goons.  Eramis will also make a lot of those big blue "Servitor" balls to shoot at you.  If you hit them right in the center, they are easy to destroy.  Goons seem to come in groups of two or three, but there are lots of Servitors.

When you are low on ammo, wait for the end of a goon wave and then jump up and run to the other corner collecting ammo as you go...crouch down again.  Remember to take a shot at Eramis in between waves. If she succeeds in freezing you, break out, kill any nearby goons, and return to your crouching spot.

Repeat the process long enough and Eramis will wear down.  When she gets below 1/4 strength, you win.  After a long cinematic, she will disappear.  This is the easy way to defeat an enemy that seems impossible.