Although having random interactions with other characters is always fun, I've always been one to pick out a specific character, will not only assist in the development of my character, but will also gain something from their interaction whether it be through battle or a battle of wits. In this case, I am searching for my perfect rival, someone who fights not for the sake of power but for others, a character with a strong heart. So if any of ya have a character you think would make a good rival for my Nihilistic Arrancar and would like a rival yourself that will always be there to challenge and push your character to their limits, come forth. I'll add a link to my character below for those interested and would like to see my character before making any decisions.
I've always believed a complete antithesis doesn't develop a character quite as well as a partial one; similarities can often show a trait or belief better than complete differences can. Besides, the dissonance of fighting an enemy like the protagonist is delicious and very fertile.
Should you agree, I submit my Shinigami Karahashi Mitsutaka for the above position. In my signature you will find his description, but I'll run up a short one now.
LIKE MORTIFERO He is introverted and believes in achieving things through his own power. He is emotionally crippled. He is logical.
UNLIKE MORTIFERO He is constantly looking for meaning in his relationships and life. He bows to no one, even should it kill him. He searches for knowledge, not power.
MOST IMPORTANTLY He has something to strive for. His ultimate goal is to fix all the problems inherent in human and other natures. He wants to create a perfect, happy world where no pain is felt and all "bad people" have been expunged. In this way is he idealistic, and he will stop at nothing to reach this goal.