Beat him at his own game

He's going to steal your skills? He just left his equipment lying around. What a waste.

You run over and grab his equipment. You can't equip them, you're the wrong class for it, but you can still hold and throw the sword like a rock or stick, and use the shield to deflect blows. You'll take almost full damage from it, and it'll wear the durability down like nothing else, but just the thought of you using his equipment should be enough to throw him off.

Since the skeleton doesn't have much Mat, its illusion wears off quickly. As soon as it does, you throw the sword at it. It only does a couple points of damage, but it interrupts its spell casting. Forcing it to start over.

You cast your basic attack and raise your shield as its dark orb fires off.

You manage to block the blow, shattering the shield and almost killing you. You have 5 HP left.

You're the same level and it has like, no Mat! How'd it do that much!

You try to remember the exact wording of your skill.

Dark orb: 5 MP launches a dark orb of power towards the target, dealing TWICE THE DAMAGE OF A BASIC ATTACK while taking twice as long to cast.

His basic attack uses Atk not Mat. So it deals twice the damage. It doesn't matter whether it's Atk or Mat. It deals twice the damage.

You may be at 5 health, but the skeleton's almost there as well.

You notice his dark orb finishing its charge while you were musing about the damage. You barely manage to dodge the attack at begin charging your attack. Yours hits first being the quicker one and it's barely left with one HP. You begin charging your next attack, realizing your mistake as they fire off at nearly the same time. You see your opponent shatter into shards just as its dark orb hits you, draining your last 5 HP and destroying you.