In terms of magical acuity, there was no question who would come out on top. Time for a practical lesson in magicamundane theory!

While Shin was correct in assuming the attack was based in magic, he had muddied the waters. This was not gestative, but transmutive. Extending crystallogenesis principles, one could weaponize even the air about them if they were creative. The crystallized oxygen was the wholly natural byproduct of placing air under incredible pressure, and altering physical matter was day one for a master transmuter such as Crystal. The hyper-thin blade may have been born of magic, but was as physical as he himself.

Given his reserved gear and weapon of choice, he examplified  the monk archetype. This gave her much to work with. Yes! Like a good monk, he would be nimble and dodge and get in close! The air blade roared onward past him to the sound of metallic grinding as it carved a scar into the earth and caused water to guyser as the gardens water leylines were cut. It fizzled out a short distance later, dissipating back into a gas with quite explosive results.

Meanwhile, Shin was intent on invading her personal space. Just as he'd begin his spin she'd fling her diamond-bearing hand forward, releasing them equidistantly as they fanned out smoothly like a liquid into curved lenses, angled between them at such a degree as to deflect his blow upward. 

Shin had miscalculated. By class, Crystal was considered a spell-blade. Not just a caster of spells, or a swordsman, but a spell-blade. This meant she could parry just as well as she could fuse the elements. It would be foolish for Shin to assume she'd come with a weapon if she hadn't intended on putting it through him! 

By this point she had reset her stance, with her scythe-blade held afront of her chest. With his momentum stoppped or severely slowed by her immoveable wedge, her riposte would come almost instantly. The first diamond barrier would fold forward, locking the staff in place at the point of contact and perhaps hampering its morphic ability upon the target area. The other would fold over his weapon-bearing hand. 

With both hands she brandished her own  and cut across whatever upper section of his body was exposed to once again attempt to bisect him. She was nothing if not determined. Every inch of the halberd was deadly, and the angle of the strike would place the curved extention behind him, severely limiting retreat options. It would be quite a crippling defeat, with him all tied up like this.

Well, he still had a free hand, so perhaps it wasn't all bad.