The unknown being easily countered the hastily-cast fireball, essentially just as Sorin expected it to. Luckily it didn't take much offense to the provocation, and went on to explain itself and its motivations. All of the talk of "dreams" that this "Viewer" rattled on about was nonsense to Sorin; he was busy trying to piece together what this being actually was, and what it was truly capable of.

The easiest answer was that it was another Planeswalker, but that left much without explanation. Perhaps it once was a Planeswalker, but had managed to ascend beyond that state by some means. Its power was certainly reminiscent of that of Planeswalkers (Sorin included) prior to the Mending. This also tied in how similar this plane was to Dominaria, while being ravaged by the Time Spiral.

Whatever its identity, the Viewer was wasting Sorin's valuable time by involving him with this folly. The Eldrazi were running amok in the Multiverse at that very moment, with Sorin doing nothing to stop them. However, if the Viewer's claims of omnipotent wish-granting were true, this event could introduce an even greater calamity. He couldn't fathom what these other people would do with the nigh-unlimited power offered by this being. In such cases as the System Lord, he was sure that it would not be good.

It was vital that he ensured that no such thing happened, though he first had to ensure that his time was not being wasted. Sorin was the plaything of nothing and no one, and he needed to establish that fact posthaste, in addition to validating the true power of the Viewer. 

"Listen to me, you cosmic mockery," Sorin called out, striding boldly forward. "If you do not know how grave an error you have made by disturbing me, allow me to enlighten you. I am Sorin Markov, Prince of All Vampires and Lord of Innistrad. Entire planes have risen and fallen at my word. I shall not be made a fool of by some interplanar jester. Give me a reason that I should not end your pitiful existence here and now."