Who is the "Top Dog" ?

[Sephiroth]

I like how the female Cloud (not a knock she is inspired by Cloud) is the only other one who can stand up against Sephiroth. I wonder if that was on purpose.

Yes, she is inspired by him but don't get me wrong here, it is not shown how she fights Sephiroth. I say that because of the power she has in Lightning Returns. She fights someone who destroys multiple planets with one attack (canonically, not as Sephiroth whose move shows his power but was never used) and simply has super powers. With her powers she is better than Cloud - except his own super power which lets him defeat Sephiroth after his canonical "limit break". So directly seen, Lightning seems better, analyzed they are on par, comparing their battle skills and their "hold my own against a god" powers.

The thing is, that Sephiroth would probably, while she is very powerful, just defeat her without thinking about it. She is incredibly powerful, but Cloud is too and Cloud has only a chance because Sephiroth never uses all his powers and abilities together like reading minds, using illusions, shapeshifting, teleporting, using his greatest weapon, his will, and such and only because he wants to torture Cloud.

Still I love Lightning.