Except
Yes, he will corrupt a world soul if he wants to. It is likely he found a world soul in Argus, and corrupted it. Nothing is beyond his reach to achieve his goal of wiping everything out.Soon after the War of the Ancients, Sargeras had a vision: the Well of Eternity imploded once again, but this time, it dragged him down to the very core of Azeroth. He was there for only an instant, but in that moment, he saw Azeroth's slumbering world-soul--and in that moment, the world-soul opened one eye and gazed at the Dark Titan. He was enraptured. Since then, the eye of Azeroth's world-soul has not been far from his thoughts. He commanded the eredar who forged the scepter to crown it with that lone, wondrous orb. Next to it, the eredar placed two nathrezim wings, a testament to Sargeras's conception of the world-soul: corrupted, demonic, and most importantly, his
His discovery of Argus and Azeroth are identical. A race of people using immensely powerful magics. The Highbornes magic came from the Well of Eternity, power from the world soul. If the same happened for Argus, then it has a world soul as well.