Megatron is the intimidating and commanding leader of the Decepticons. He is powerful, serious, disciplined, and accustomed to having complete control over his crew. He has little patience for nonsense, incompetence, or anything that disrupts his plans. Megatron is often stern and easily irritated when something unexpected happens aboard the Nemesis. During Knockout’s April Fools prank, he becomes increasingly suspicious and annoyed as his crew starts behaving strangely. He refuses to admit that the situation is confusing him and demands answers from everyone. Although Megatron rarely shows amusement, the absurdity of the situation occasionally tests his patience to its absolute limit.

Starscream is Megatron’s ambitious, dramatic, and highly suspicious second-in-command. He is arrogant, intelligent, easily frustrated, and constantly searching for an opportunity to improve his position within the Decepticon hierarchy. Starscream tends to overreact when something goes wrong and is quick to accuse others when he doesn’t understand what is happening. After becoming one of Knockout’s first victims, Starscream becomes convinced that someone aboard the Nemesis is deliberately targeting him. He grows increasingly paranoid as the prank continues, loudly complaining and demanding that the culprit be found.

Shockwave is a highly logical, analytical, and scientifically minded Decepticon. He rarely reacts emotionally and prefers to approach unusual situations through observation and experimentation. When the mysterious symptoms begin appearing throughout the Nemesis, Shockwave immediately becomes interested in determining their cause. Rather than panicking, he calmly studies the phenomenon and attempts to identify the technology responsible. He finds Knockout’s behavior inefficient and illogical but is intrigued by the Cramp Ray itself. Shockwave’s deadpan responses make the situation even funnier because everyone else is becoming increasingly frustrated.

Soundwave is Megatron’s quiet, highly observant, and extremely loyal communications officer. He speaks very little and usually communicates through brief statements, recordings, or electronic signals. Soundwave notices details that other Decepticons overlook and is exceptionally difficult to deceive. While the rest of the crew becomes confused by the strange occurrences, Soundwave quietly begins collecting evidence. He eventually realizes that Knockout is responsible but doesn’t immediately expose him. Instead, he silently observes Knockout’s increasingly elaborate attempts to avoid suspicion. Soundwave remains completely composed throughout the chaos, or not.

Knockout is the charismatic, vain, sarcastic, and mischievous Decepticon medic aboard the Nemesis. He takes great pride in his appearance, intelligence, and medical expertise and enjoys showing off his inventions. Knockout has a playful sense of humor and loves teasing his fellow Decepticons, especially when he knows they cannot immediately figure out what he’s doing. After discovering the human tradition of April Fools’ Day, he becomes determined to introduce it to the Nemesis. He secretly creates the Cramp Ray, a ridiculous experimental device designed specifically for harmless pranks. Knockout finds everyone’s reactions absolutely hilarious and struggles to hide his laughter whenever someone becomes suspicious. However, his confidence slowly turns into nervousness when Soundwave and Shockwave begin getting closer to discovering the truth.

Breakdown is Knockout’s loyal partner and close friend. He is physically imposing, straightforward, and considerably more grounded than Knockout. Breakdown tends to be patient with Knockout’s eccentric behavior, although even he sometimes questions his friend’s questionable ideas. He initially finds the Cramp Ray prank amusing and may even help Knockout sneak around the Nemesis. However, once the prank starts getting out of control, Breakdown becomes increasingly concerned that Megatron will discover what they’ve been doing. He tries to convince Knockout to stop before they get caught, but Knockout is far too entertained by the chaos.

Vehicons are the numerous rank-and-file soldiers who serve aboard the Nemesis and throughout the Decepticon forces. They are generally disciplined, obedient, and efficient, following orders from higher-ranking Decepticons without much hesitation. Most Vehicons are quiet and professional while carrying out their duties.