I don't remember that scene, however even if is so, Marcone isn't invulnerable. For one thing Harry still has the Sword of Love in reserve, he says he is no Holy Knight, but if the cause is there, he may find he is one, if only for this eventual confrontation. Harry has a little invulnerability of his own, the Spear gives him that. Denarians can be taken down, Harry came very close to doing Nic in a couple of times. Thorton Namshiel was taken down, that is how Marcone got the coin in the first place. Yes, Harry has a lot more studying to do before he can take on Namshiel, but he knows his host very well... They did soul gaze once, yes, Marcone frightened him, but Harry also saw his weaknesses was well.. Yes, Marcone saw his, but he also knows it is better to have Harry on his side than his enemy..
But that's the point isn't it, he had it, that is what Jake was trying to tell him in Small Favor and in Ghost Story... Balance, like the Holy Knights Harry is there to balance the threat of the Fallen. Also Old Thorton was most likely a wizard before he took up the coin, he just got more juice from Namshiel the Fallen Angel.. Marcone may have had some talent, but he is no wizard, as Harry taunted him with the fact. He still has a lot to learn, so the battle may not be as one sided as you think.
Marcone stabbed at her. A child would have done better against a professional wrestler.
Ethniu’s good arm blurred. She seized him by the throat, lifted him with no noticeable effort, gave her arm a little bob, a little twist, and broke his neck.
I watched Marcone jerk and go limp.
She rose to a knee, her good leg planted in the boiling water, and threw the corpse away like an empty beer can.
The Baron of Chicago landed on the rocks, boneless and broken.
A roar went up from the battlefield behind us.
The blue beam of light rising into the night like a vague, glowing moonbeam, above the embattled forces of the Winter Lady, flickered and dimmed.
Ethniu let out a bubbling, almost disbelieving laugh. Then she prowled like a beast down into the roiling water and slipped beneath it. I could see her reaching out a hand toward the light of the Eye.
I staggered over to Marcone’s body. Broken neck didn’t kill you right away.
Nobody ought to die alone.
And when I got there, he sat up. I fell back with a manly high-pitched scream.
Marcone’s head was twisted way too far around to one side. He rolled his neck as if stretching out. There was series of hideous little pops in his neck and then he shook his head back and forth as if easing a cramp, and his neck just . . . unbroke. Marcone gave me a bland look and held up his knife.
Its blade was covered in blood, too bright red to be real.
I blinked and stared at the knife. Then up at him.
“What the actual fuck?” I asked.
I felt my eyes widen.
Celestial power, they had said, to get through the Titanic bronze.
Or infernal.
Marcone’s eyes wrinkled at the corners in genuine amusement. “Honestly, Dresden. Did you think I’d stop with the title?”
No one is saying Marcone is invulnerable. Just that he could survive a broken neck and Harry could not.
Does the Spear grant invulnerability? So far all we have seen is that it can strike through Titanic Bronze and has enough power to help Harry bind such a being. I am aware that is supposedly grants victory to whoever holds it...but that might just as easily be because it has so much power as simply bending reality and probability to force victory. We haven't seen any evidence yet of the latter.
I don't disagree that Denarians can be taken down and I do believe that in taking up a Coin, Marcone has sealed his own fate (I don't see him repenting any time soon). That being said Marcone was formidable as a mortal already. Now he's had a Coin for the last decade...he's probably a whole lot scarier. I mean he already seemed scarier than in Small Favor even before we knew about Namshiel.
I don't remember Marcone having any weaknesses that Harry saw in the soulgaze. I only remember him being ashamed and furious about the hurting the Beckitt child, and that it drove him. Not sure that's a weakness.
I don't thinks it's established that Marcone isn't a wizard. We haven't seen him do anything but Harry doesn't watch him 24/7 and has never even touched Marcone so he wouldn't have picked up any energies. Marcone may well have had talents, maybe not White Council level, before he took the Coin. Marcone isn't like Harry he would never reveal such a thing. It might even be latent.
Not to mention, that yes while Marcone has a lot to learn - he has Namshiel. Namshiel doesn't have a lot to learn as he already literally knows all there is to know about magic (that an angel can know). He has intellectus. That's
huge! We have seen Lash speed up Harry's brain so he can react faster than a normal being, think of what Namshiel could do. Even if Harry is better and more prepared, these are significant advantages. Marcone will get a lot more out of Namshiel than whoever the poor sap was who last was his ride. The fact that Macone goes by Marcone, and not Thorned Namshiel, should tell you a bit. He's on the order of Nicodemus but with magic. He might actually be a worse threat.
I do agree it won't be one-sided. Harry is formidable. Just look at his track record. But Marcone is no pushover (especially now), Harry will have to use every trick he has learned to beat him.