Suggested by iKnowledge Metamorpho is a pretty strong opponent who has actually gone up against the Justice League in the past. His ability to use all of the elements makes him a very versatile threat. He is rather similar to Korra in that respect, but she has the edge here. In her ascended state switching between the elements is very easy. Her offensive capabilities are greater than Metamorpho’s and he will just have a tough time focusing on his attacks when she is blowing him all over the place with her impressive air abilities. Korra wins.
Suggested by Eric This is definitely a pretty tough round. Both of these avatars have proven themselves in combat many times over. They’ve mastered all of the elements and can use the Avatar state. Korra seems to have gotten off to a faster start but by the end they were both very skilled. I’m inclined to say that Aang wins as his abilities just sound more impressive overall, but this is one of those fights that could easily change if I were to watch the show myself someday. Alternately, it could just cement Aang’s win even more. At the very least, I don’t see either of these two losing to any other Avatar characters. Aang wins.
Suggested by Eric Korra is a skilled avatar, but she is no match for Krillin. Krillin may technically be a human in DBZ world, but his abilities are on a higher level. He can destroy whole planets and his speed is at an insane level. Korra simply wouldn’t be able to keep up with him at all. It’s a pretty big mismatch and I dare say that Krillin could win this round whether he was bald or had hair. That’s just how powerful he has become over the years. Krillin wins.
Rin Tohsaka is a skilled magic user whose gems can damage even the strongest of opponents. That being said, she would be thoroughly outclassed in a one on one fight against Korra if she didn’t have her servant fighter at the ready. Much like a Digimon partner or a Netnavi, characters from the Fate series typically have a legendary hero as their support. Rin got Archer in the original Fate Stay Night anime and he is quite formidable. His raw speed and power will be enough to overwhelm Korra despite her mastery over just about every element. Speed can definitely play a key role in a fight and as far as this one goes, it was certainly all that he needed, although he won’t get the credit for this victory. Rin Tohsaka wins.