SPOILER WARNING: This article contains major spoilers for "From the Ashes," the latest episode of Agents of S.H.I.E.L.D.
The FitzSimmons family just figured out how to stop Izel. In "From the Ashes," the latest Agents of S.H.I.E.L.D. episode, Deke realized the source of Izel's power: resonant frequencies. Immediately, the three masterminds set to building a device that will disrupt her frequencies and prevent her from going intangible.
Deke made this discovery as he re-watched footage of Daisy's confrontation with Sarge. When Daisy brought up Sarge's special sword to behead him, Deke noticed it made a sound and rewound it: "Did you hear that?"
"Of course!" he cried a moment later, grabbing the Shrike-killing knife. He banged it against the edge of the table, then listened to the sound it made. "Resonant frequencies. That's how her powers work!"
Realization dawned on Simmons' face. "Just like the monoliths," she said breathlessly. "It's how Izel can incorporealize and occupy the same space as her host."
"Think about it! Atoms are mostly just empty space and if they're going to pass through each other or intertwine --" Deke started, for Fitz to finish, "She's aligning her atoms to harmonic resonance."
"So we just need to disrupt the harmonic frequency like these do," he said, brandishing the knife.
"That's why they're so effective against the Shrike," Simmons supplied.
"We need to design something compact," Deke mused.
"To send audible frequencies that reverberate through our bodies," Fitz added.
"Matching the frequency of this alloy," Simmons pitched in.
"It'll create a sonic barrier!" Deke said.
"I'll get started on a design. It needs to be wearable," Fitz mused. When Deke suggested a belt buckle, Simmons replied, "I like it."
"We can build a prototype within a couple hours, once we have a design," Deke affirmed.
"Let's get started," Fitz said with a smile, handing him the stylus. At that, all three of them set to work to create the weapon that could stop Izel once and for all.
The FitzSimmons' discovery also has implications for Sarge. After all, Sarge is a composite creature, an amalgamation of Izel's partner Pachakutiq and a doppelganger of Coulson created by the monoliths. As a result, he has two opposing forces battling within him: the one that wants to join Izel's cause and the one who will stop at nothing to kill her. He even described Pachakutiq as "all rage," seething just under the surface.
Through a series of trials, Daisy was able to bring the Coulson side of Sarge to the surface. In the heat of the moment, as he begged Daisy to kill him, he called her "Skye" -- a sign that he does, indeed, carry Coulson's memories. However, that evil force Pachakutiq still rages within him, fighting to overcome Coulson's better instincts and unleash its terrible power.
But Pachakutiq is a separate entity, which -- according to Izel -- merely possessed the vessel that appeared on their planet. As such, it may be possible to use one of FitzSimmons' sonic disruptors to purge Pachakutiq from Coulson's doppelganger. With Coulson's memories intact, he would be able to rejoin the team -- but only if Izel doesn't kill him and Pachakutiq both.
Marvel's Agents of S.H.I.E.L.D. airs Fridays at 8 pm ET/PT on ABC. The series stars Ming-Na Wen, Chloe Bennet, Henry Simmons, Iain De Caestecker, Natalia Cordova-Buckley, Elizabeth Henstridge and Clark Gregg.