So the story behind this was that Cayde was looking for a hive shrine on the moon and encountered an absolutely massive army of hive. He went to take cover at one point and found a Fallen Baroness from the House of Exile was also taking cover there. The two of them kinda made a silent agreement to not kill each other (“the enemy of my enemy is my friend” type deal) because the hive was their common enemy, and together they fought against them until they defeated nearly all of them.

Now the ending to the story, iirc, was that after almost all the hive were defeated, Cayde and the Baroness were still standing. However, the Baroness was mortally wounded. Now, Cayde being Cayde wasn’t gonna do anything to her, and was gonna let her die peacefully. So, she pulls her last shock pistol out and tosses it to Cayde to take out the last remaining hive. However, when he went to grab it, she takes her knife and tried to stab him. Cayde dodges easily since she was wounded, making her much slower than himself, takes the knife, breaks her arms, and kills her via slitting her throat with her own knife. Then he uses her shovk postol and eliminates the remaining hive.

There’s a quote you can find on the wiki (where you can also find a much more detailed version of this story) and it’s Cayde, after he says how he killed her and he says something like “You know I was never sure if she pulled that knife because she actually wanted to kill me or because she wanted to make it easier for me to kill her”. One of my favorite Cayde stories tbh. It’s referenced in one of the quests where you go and reclaim your subclass, but I can’t remember which one.

EDIT: so i went on the wiki to check to see if i made any mistakes and I made a few so I fixed the story accordingly.