Shigaraki’s Decay Wave Explained: How He Destroys the City in My Hero Academia

Tomura Shigaraki’s transformation in My Hero Academia reaches its most terrifying peak during the Paranormal Liberation War arc. What begins as a villain’s gradual evolution turns into a catastrophic display of power when Shigaraki unleashes his Decay wave across an entire city. This moment is not just visually surprising, but also marks a turning point in the story’s scale and stakes.

After undergoing experimentation under All For One’s guidance, Shigaraki gains enhanced physical abilities and a significantly upgraded version of his Decay Quirk. During his awakening, he no longer needs direct contact with all five fingers to activate Decay. Instead, the destruction spreads across the ground and anything connected to it, creating a chain reaction that wipes out everything in its path. As depicted in Kohei Horikoshi’s manga, this ability allows Shigaraki to level entire urban areas within seconds, making him one of the most dangerous characters in the series.

What Is Shigaraki’s Decay Quirk?

Shigaraki’s original Decay Quirk allows him to disintegrate anything he touches with all five fingers. In earlier arcs, this power is limited by both range and activation conditions. He must maintain physical contact, and the effect does not spread beyond the initial target unless he consciously chains it.

However, during the My Villain Academia arc, Shigaraki undergoes a psychological and physical awakening. He recalls suppressed childhood memories, which unlock the true potential of his Quirk. From that point onward, Decay becomes far more destructive, spreading automatically through connected surfaces.

This evolution changes Decay from a single-target ability into a large-scale area-of-effect attack. The Quirk now behaves like a wave, traveling across the ground and structures, disintegrating everything it touches. This is the foundation of what fans refer to as the “Decay wave.”

Pro heroes struggle to escape as Shigaraki’s Decay wave rapidly consumes everything in its path. (Image via Studio Bones)

The most iconic use of Shigaraki’s Decay wave occurs after he wakes up during the Paranormal Liberation War. As soon as he touches the ground, the Decay spreads outward at an alarming speed. Buildings crumble, roads collapse, and entire city blocks vanish almost instantly.

What makes this attack especially dangerous is its chain reaction nature. The Decay travels through anything physically connected, including infrastructure, debris, and even people. This creates a domino effect where destruction multiplies rapidly, making it nearly impossible to escape once the wave begins.

Heroes caught in the area are forced to retreat or rely on extreme mobility to survive. Characters like Endeavor and others struggle to respond because the attack covers such a massive radius. The scene demonstrates how Shigaraki’s power has surpassed conventional combat and entered the realm of large-scale devastation.

Why Shigaraki’s Power Evolved So Drastically

Shigaraki’s transformation is not just a random power boost. It is deeply tied to his character arc and his connection to All For One. The experiments conducted on him enhance his body, allowing him to handle multiple Quirks and withstand greater strain.

At the same time, his emotional awakening plays a crucial role. By embracing his past trauma and identity, Shigaraki removes the mental limitations that once held his Quirk back. This combination of scientific enhancement and psychological breakthrough leads to the Decay wave’s emergence.

According to the series’ lore, Quirks can evolve under extreme stress or emotional triggers. Shigaraki’s case is one of the most extreme examples of this phenomenon. His Decay becomes a symbol of his complete rejection of society and his desire to destroy everything connected to it.