Hmm you like companions a lot it seems
I do have a few in mind but my all-time favorite is Midna from Twilight Princess....
(Spoilers ahead) Not only I she one of the most effective amd useful companions in the history of Zelda games but she was just an amazing character all round! As we all know Midna was a very mysterious figure, we had to think about her intentions throughout the game as it was if she was some how evil, during the start of the game she treated Link as a slave and was generally just a jerk! But as the story progressed and through many tough times her and Link grew to like another. This all came to a great ending in where Midna risked her own life to save Link and defeat Ganon, in the ending cut scene Link appeared to see Midna in the distance and Link runs over as if his life depended on being reunited with Midna. We then see Midna in her true and beautiful form and the we see Link just smile at the end, this made for one of the greatest and most satisfying endings in gaming <3 However we all know what happened later on after the credit's...Midna goes to say something to like "Link....." However she stops and sheds a tear that ultimately shatters the Mirror, which was the only connection between the two. Egen though a sad ending overall it left us thinking what the true feelings were between Midna and Link, one of the strangest but greatest friendship we have seen between Link and another character in my opinion.
Midna was a great example of how important a companion can actually be to the story and it was one of the greatest tales of how a the personality and intentions of a character can develop throughout the events of a game. It made the connection and friendship between Link and Midna even stronger as tou saw how their relationship evolved for the better over time, I truly think that Midna is one of the best characters we have seen in Zelda as of yet <3