"The little girl who had the misfortune to experience what happened on that MAX, her life is never going to be the same," said Fletcher, filmed in a bedroom while wearing a bathrobe.
Two African-American teenagers, one of whom is Muslim and was wearing a hijab, were verbally attacked last Friday by Jeremy Joseph Christian, authorities said.
"Imagine that for a second -- being the little girl on the MAX," Fletcher said. "This man is screaming at you, his face is a pile of knives, his body is a gun. Everything about him is cocked, loaded and ready to kill you.
"There's a history here with this, you can feel that this has happened before, the only thing that was different was the names and faces. And then a stranger, two strangers, three strangers, come to your aid, they try to help you and that pile of knives just throws itself at them, kills them."
Three men stood to defend the girls. Christian slashed the throats of Taliesin Myrddin Namkai-Meche and Ricky John Best, killing them, police say.
Fletcher's survival may have come down to millimeters. The attacker's blade, he said, sliced into his neck but just missed his carotid artery.
'Make it spread like wildfire'
Fletcher said he appreciates the kindness directed toward him and the families of the two men. This outpouring can be attributed, "to put it bluntly, (to) this white savior complex," said Fletcher, who is white.
"We need to remember this is about those little girls," he said. "I need you, if you really want to support me, to like this, to share it, whatever, and make it spread like wildfire."
A YouCaring page
has been set up to collect money for the girls.
"The funds will go toward basic necessities like meals and transportation, as they feel unsafe to ride public transportation after their experience," the page said. "Most importantly, funds will go toward mental health services to ensure their mental and emotional welfare."
In an interview with ABC News, Fletcher also spoke about defending his community.
"If you live here, move here, or if you want to call this city home, it is your home," he told ABC News. "And we must protect each other like that is the truth, no matter what the consequences."
"The Muslim community, especially in Portland, needs to understand that there are a lot of us that are not going to stand by and let anybody -- whether they are from here or not -- scare you into thinking you can't be a part of this town, this city, this community, or this country," he told ABC.
'I call it patriotism'
Christian was arraigned Tuesday and yelled as he walked into the courtroom, saying: "Get out if you don't like free speech!" and "You call it terrorism; I call it patriotism. You hear me? Die."
Christian was arraigned on several charges, including two counts of aggravated murder, attempted murder, two counts of second-degree intimidation and being a felon in possession of a restricted weapon, police say.
His next court appearance is set for June 7. A Multnomah County grand jury will convene in the coming days to consider additional charges, and federal authorities are still deciding whether to prosecute Christian for hate crimes.
Christian said he was transient and "does not know the last time he had a permanent address." Court documents from previous years show he lived with his parents.
Rallies in Portland
As Portland comes to grips with the attack, at least three rallies are set for Sunday: a pro-Trump rally in Terry Schrunk Plaza, and two demonstrations by anti-right-wing coalitions, one in front of City Hall and the other at Chapman Square.
Police are geared up to handle any confrontations.
Patriot Prayer plans to hold a Trump Free Speech Rally at 2 p.m. in Terry Schrunk Plaza, organizer Joey Gibson told CNN. The Federal Protective Service plans to provide officers to help local police, Portland Police Chief Mike Marshman told CNN affiliate KATU.
Portland Stands United Against Hate is planning a demonstration in front of City Hall at 12:30 p.m., and a rally dubbed Portland Stands United Against Fascism is planned for noon in city-owned Chapman Square, according to announcements on Facebook.
Portland Mayor Ted Wheeler had opposed the Schrunk Plaza event, citing concern over community tensions following the train attack. He asked the federal government to revoke the permit for the demonstration, CNN affiliate KOIN reported.
But the federal General Services Administration declined, saying "the permit was lawfully obtained to assemble at this federal location. GSA has no basis to revoke the permit," KOIN reported.
Wheeler also opposed a March Against Sharia set for June 10 in Portland.
That event has been canceled, Scott Ryan Presler, an organizer of the Portland March Against Sharia, said in a Facebook post. He invited those planning to participate to "join us in Seattle."
The March Against Sharia, sponsored by ACT for America
, is a national event and will be held in cities across the United States.
CORRECTION: In an earlier version of the story, CNN incorrectly reported the location of the Trump Free Speech Rally, which will be held in Portland on Sunday.