Who Is Stewart?
Short Answer
Stewart is an older Devs engineer who sabotages the elevator carrying Lily and Forest because he believes the project has gone too far.
Connected Story Threads
Stewart's insider status lets him see both the machine's achievement and the moral cost of protecting it.
Stewart disables the transport and causes Lily and Forest's physical deaths.
Stewart attacks the system Forest built around grief, prediction, and control.
Katie survives Stewart's sabotage and answers it by preserving the simulated world.
Stewart causes the crash because he believes Devs must be stopped.
The transport system becomes the physical mechanism of Lily and Forest's deaths.
Direct Answer
Stewart is an older Devs engineer who sabotages the elevator carrying Lily and Forest because he believes the project has gone too far.
Evidence From The Series
In the finale, Stewart disables the transport system, causing the crash that kills Lily and Forest physically and forces Katie into the simulated ending.
Why It Matters
His act is not clean rescue; it is a fatal refusal to let Devs continue as Forest imagined.
Related Characters, Places, and Concepts
More Questions About Stewart
Stewart stops the elevator because he believes Devs has crossed an intolerable boundary and must be interrupted.
The elevator crash means the predicted shooting is not the final physical event, but breaking the forecast still leads to death and simulation.
At the end of Devs, Lily refuses to shoot Forest, Stewart crashes the elevator and kills them physically, and Katie keeps them alive inside a simulation.
Sergei copies the Devs code because he is spying for Russian intelligence and needs proof of Amaya's secret project.
No. Lily dies physically in the elevator crash, but a version of her continues inside the Devs simulation Katie keeps running.
The title Devs refers to Amaya's secret development division and also echoes the show concern with creators who behave like gods.