Count Olaf
Count Olaf is appointed as the children's guardian after their parents die in a tragic house fire. However, he ironically acts nothing like a guardian, terrorizing the children and attempting to steal their fortune.
Intelligent children
Ironically, in this book the children are actually smarter than the adults. The children quickly realize they are in a precarious situation, and ask for help. When help is not given to them by the adults in their life, they are forced to come up with a plan on their own to escape.
Poe
Poe is trusted with the role of looking after the children, which he does very poorly. Ironically, he places the children in the care of a man who wants to steal their fortune and kill them.
Void marriage
Count Olaf tries to force Violet to marry him in an attempt to secure the Baudelaire fortune. However, he doesn't realize that she signs with the wrong hand, making the marriage void.
Justice Strauss
We might expect Justice Strauss to be a perceptive and observant person due to her profession as a judge. However, she ironically does not see what Count Olaf has planned and even takes part in the wedding ceremony.