Gaven did not attempt to change Kellanwo, because he knew people like him had incredibly steadfast wills. Even close associates would find it hard to influence him, let alone an outsider he had just met.
Moreover, Kellanwo's emotions towards Prince of Lies Shylock were visibly complex; hatred and disgust intertwined with a shred of unbreakable friendship, even harboring a faint hope for his eventual repentance and assumption of his Lord of the Dead duties.
Such personal emotions are even more inaccessible to outsiders, unless one day he comes to terms on his own.
For this, Gaven was not worried, as he knew the kind of madness Shylock would bring in the future, and the magnitude of destruction and death it would cause on the Felen Continent.
With Kellanwo's compassionate nature, he would never stand idly by; he would inevitably embrace the attitude of 'If I don't go to Hell, who will?' and this would propel him to the divine throne of the Lord of the Dead.
