Xoti's story is quite remarkable as well. Her faith and her role as a priestess are central to her character. Her journey with the Watcher is filled with moments of self - reflection and growth. The way she deals with the darker aspects of the world while maintaining her positive outlook is a great part of her story.
Well, for me, a great backstory is key. If a companion has a rich past filled with events that shaped them, like Eder's time in the war, it makes their story interesting. It gives a context to their actions and attitudes in the present of the game.
Aloth is another character with a fascinating companion story. His struggle with his own identity, being a wizard with a dual personality, is a central part of his narrative. His journey to come to terms with himself and his place in the world makes for a great story as you play through the game with him.
In my opinion, the Ranger class can be great for the story in Deadfire. Rangers have a strong connection with nature which often ties in well with the game's themes and story elements. Their animal companions also add an interesting dynamic to the story progression.
Pallegina has a very unique story too. Her connection to the Vailian Republics and her sense of duty are central to her story. Her conflicts between her personal beliefs and the orders she has to follow add a lot of intrigue. Also, her cultural background gives a different flavor to her story compared to other companions.
One of the best FNV (Fallout: New Vegas) companion stories is Boone's. His backstory of being a sniper in the NCR and his tragic past with his wife makes for a very engaging narrative. It adds depth to his character and his actions in the game.
Gale is another good one. His story is filled with magic and mystery. His relationship with the Weave and his past mistakes make him a very interesting character to have around during the story. He often provides insights into the magical elements of the game world, which can enhance the overall story experience.
Piper is a great choice for the story. She's a journalist with a curious nature. She'll often comment on the events in the story, adding some interesting perspectives. And her personal quest also ties in well with the overall narrative of Fallout 4.
The Cipher class can be really good for the story too. Ciphers have this unique mental power that can be used to understand the minds of others and manipulate them. This power can lead to some really interesting story developments as they interact with different characters in the game.
For me, Lae'zel's story has a lot of emotional depth. She is a githyanki warrior, and her story is full of her struggle to uphold the values of her people while also seeing the flaws in their ways. She has to deal with her own sense of identity and where she belongs in the grand scheme of things, which can be really moving at times.