When Griffin convinces Mr. Marvel—a poor bachelor—to help him in Chapter 9, he uses pathos. First, he appeals to empathy. Griffin begins his pitch like this:
‘Here,’ I said, ‘is an outcast like myself. This is the man for me.’
Certainly, an “outcast” is not something generally regarded as positive. He is not flattering Griffin yet. He is instead appealing to Marvel's sympathy by showing that they are alike. They both suffer at the hands of society because of their differences: Mr. Marvel is a poor wanderer, and Griffin is a man with albinism who has become invisible.
Griffin hopes that Mr. Marvel will help him just because of their similarities and general human decency, but because Mr. Marvel is surprised and fearful of the invisible man, he does not initially agree to help him.
Then, Griffin pivots to flattery and promises of wish fulfillment. As he says:
“I’ve chosen you,” said the Voice. “You are the only man except some of those fools down there, who knows there is such a thing as an invisible man. You have to be my helper. Help me—and I will do great things for you. An invisible man is a man of power.” He stopped for a moment to sneeze violently.
Griffin emphasizes that Mr. Marvel is special and now is gifted with a certain type of special knowledge—knowledge that Griffin has not gifted to anyone else. This, in turn, makes Marvel feel as if he should help Griffin. This appeal is directed at Marvel’s ego.
What's more, Griffin also appeals to Marvel’s desire for power, promising to grant him anything he could desire. This offer parallels the structure of a Faustian contract. A Faustian contract is a motif in literature in which a character makes a deal with the devil (or a devil-like character) for the fulfillment of a desire. There are times in the text when Griffin seems to be associated with God, though here he seems to be aligned with the devil.
Right after using empathy and flattery, Griffin turns to intimidation as a tactic, suggesting that he would hurt Mr. Marvel in the instance of betrayal. Mr. Marvel cuts him off mid-threat to agree to help him. The intimidation appears to convince Mr. Marvel. This fact sets Mr. Marvel up as a character that is primarily motivated by the avoidance of pain.
