Chell, documented as Test Subject #1 but previously as #1498, is the silent protagonist and player character in both Portal and Portal 2. She is described by GLaDOS as a "dangerous, mute lunatic".
The "Bring Your Daughter To Work Day" science project signed by Chell in Portal 2 implies that Chell was the child of an Aperture scientist. Originally rejected as a test subject, Doug Rattmann altered the tests, having correctly guessed that Chell's extreme tenacity might allow her to defeat GLaDOS.
Chell's Test Subject Application Form states that she refused to answer the essay question and instead answered in binary, which translats to "The cake is a lie".
She is modeled after Alesia Glidewell and voiced by Mary Kae Ivrin.