At the bottom of the skill chain is aura users as a whole. While every living being in RWBY technically has Aura, actually being able to utilize it for things such as defense, regen, and senses requires years of training and a high enough degree of martial skill (and yes you actually need martial skill for it) that only a small percentage of the population of the entire planet ever become skilled enough to utilize their aura. Of that small percentage, an even smaller percentage ever become skilled enough to manifest/control a Semblance (yes semblances are also skill-based). To reach this small percentage comes to the second half of the bottom of the chain: Almost every character worth their salt in RWBY has spent their entire life training in combat and can fight hordes of Grimm with little issue (Almost because Jaune exists). The entirety of the main cast of RWBY was initially enrolled at Beacon Academy, one of the most prestigious combat schools in the world, with almost everyone who was accepted there having been trained for almost their entire life to fight monsters, and each one that was not professionally trained requiring a skill display overseen by Ozpin, who has the composite skill of several thousand professional huntsmen that he accumulated over his immortal lifetime and has trained with Kami and is more skilled than end of og Dragon Ball Goku
Thats the baseline for skill in the verse.
Moving up the chain we have Nebula Violette, who not only outmatched Velvet in a 1v1 test of martial arts skill, but was directly stated to be more skilled than Velvet in combat despite Velvet mixing numerous fighting styles to try to throw her off in their fight.
Above her is Pyrrha Nikos, the skill god of the Beacon Arc. Pyrrha is one of the most skilled students at Beacon Academy, having won every combat tournament she has entered since she was a pre-teen due to both her mastery of combat and mastery of her semblance, being able to apply it in combat completely undetected and having done so in almost every fight she's been in for over a decade, doing so with such skill and precision that she has lead many to believe she is untouchable and invincible as no one has been able to even land a blow on her in her combat career. Even without her semblance she has shown the ability to quickly and easily adapt to her combat situation and analyze her opponents while fighting and changing tactics to suit the situation she is in. She has shown extreme accuracy, being able to hit moving targets from hundreds of meters away and strike vital weak points on an opponent mid-combat both with and without the aid of her semblance. She is also highly skilled at using her weapon's multiple forms in combat, being able to switch between forms several times in rapid succession to both deliver rapid attacks and counter others simultaneously. Blake fought evenly with Phyrra in Beacon
Blake then trained more after this, so she clearly became more skilled
