Originally described as being enthusiastic, the videos from the Marble Hornets filming in 2006 display his descent into madness, paranoia, anger and other forms of psychosis.After being stalked by The Operator, it is shown that he is very violent, incapacitating several of his friends in various videos, including Tim, Brian, and Jay. It can be assumed he killed Seth and Sarah as well, and it is revealed later in the series that he even killed his girlfriend Amy after she came into contact with the Operator. His violence is shown in great detail when he assaults and murders a man outside the tunnel.The greatest explanation of Alex's personality likely comes during Entry #86, where he sees himself as a force of good. Apparently having discovered The Operator's memetic spread, he takes it upon himself to kill everyone who has come into contact with The Operator, and save the planet. As Tim points out, however, The Operator is likely using Alex to spread further, as he has been causing more havoc than he had intended.
History
Alex appears in almost all of the entries up to Entry #20, when the series began to focus on Jay and his investigation. He makes appearances in most entries between #35 and #52, and has appeared occasionally since Entry #52.In Entry #86 Alex's true motivations were revealed. In actuality, Alex had been attempting to stop the Operator from spreading to other people. In the process, however, he became more and more deranged until he decided everyone who had a connection to it needed to die, including himself. He succeeds in killing Amy and Jay; Tim kills Brian and it is assumed that Alex killed Seth and Sarah too.He died after a long confrontation between Tim and himself , in the process, Tim attempting to convince him that he wasn't helping anything. However, Tim was forced to stab him in the neck and finished him after he fell to the floor, writhing. With his last words, Alex implored Tim to carry on his mission and to kill everyone connected to the Operator, then kill himself. However, given Tim's contrasting views, he likely did not agree with him.
Trivia
Alex has the most gruesome death seen in the Slenderverse.Despite initially being a protagonist, Alex turns out to be the true villain because he had bigger plans than the Operator, and even planned to kill the Operator.