You haven't specified which character you would like me to focus on in this intriguing and, in many ways, inscrutable story by Chekov, so I will focus on the main character, which is the Banker. This story has an interesting narrative style, as it starts at the end as it were and then uses flashbacks to fill us in with what happened before. The banker at the party which is the main element of this flashback is garrulous, wealthy and imprudent with that wealth. Note the way he is quick to make "the bet" without hesitation:
"It's not true! I'll bet you two million you wouldn't stay in solitary confinement for five years."
The banker himself, years on, is able to look back and call this bet "wild" and "senseless," and the narrator tells us how the banker felt immediately after making the bet:
The banker, spoiled and frivolous, with millions beyond his reckoning, was delighted at the bet. At supper he made fun of the young man...
However looking back on the bet, he recognised it as a "caprice of a pampered man." However, ironically, in spite of the reflection that the now poor banker is able to have, perhaps because of his penury, at the end of the story he still shows that greed dominates his actions. Note how at the very end of the story he takes the note the lawyer left and locked it in his safe, presumably so that if the lawyer came back having changed his mind, he would have proof that he had renounced the money and his property would be safe.