Chaosmancer
Legend
It's less unlocking and more the difference between a sword maker and sword user.
The martials are the only ones skilled in swordsmanship to wield magic swords. The "Special Technique" is a thousands year old trope.
A wizard can't slash a hole into the Feywild. A fighter can.
"You can't cut right into reality!"
It's a magic sword.
I mean D&D fighters take fireballs and dodge them without moving. Wouldn't a logical explanation be them batting away half the fighter with their magic axe?
I'll never forget the episode of Slayers where Gourry is mind controlled and uses the Sword of Light vs his magic user friends to parry and reflect all their spells back at them and AOE them into full panic mode. So they had to me saved by another high level fighter who could enter melee with him..
Because Gourry is a high level fighter and he has a magic sword. And a pea size brain.
Okay, question. Why does it have to be a magical weapon?
I mean, in theory that entire fight, as bad-ass as it was, would have ended instantly if it wasn't The Sword of Light and was just... a sword. It would be like saying "look how bad-ass this fighter is, with his armor of immunity to all magic, he can't be taken out by mere magic-users, you need a bad-ass fighter to take him out" Like... are we really going to pretend the quality of the swordsman matters there?
And sure, they say that he is drawing out the sword's full power yadda yadda yadda, but the trick is in the phrasing. It is the SWORD'S power, not HIS power. What is Docter Strange without the Eye of Agamoto? Still the flippin' sorcerer supreme.