most infamously to happen in their friendship was their date to prom. robyn was the one to ask dylan to go with her. he questioned what day it would be on, presumably since the massacre would take place not too far from the event. his parents gave him a hundred bucks toward the night out. with the formal dance taking place at the denver design center, robyn would describe dylan as having been "very gentlemanly" to her throughout their evening together.

dylan and robyn dressed up together at the formal dance.

tiffany burk, robyn's best friend, says she'd told her that her and dylan "had a wonderful time." she also said that, "they were incredibly kind to one another. dylan had tons and tons of respect for robyn. she was someone who he confided in."

transcription: so finally i convinced my friend dylan, who hates dances, jocks and has never had a date let alone a girifriend to go with me! i am either really cute or just really persuasive!

an unreleased home video filmed by dylan's father shows robyn putting the pink rosebud boutonniere on dylan's tuxedo for him. when he notices his father holding a camcorder pointed right at them, dylan comments, "dad, why are you filming this? well, someday i'll watch it again, and i'll wonder what i was thinking."

jessica hughes, one of the ten others to accompany the pair on their limo ride to the venue, says of them, "they were holding hands and stuff . . . they were pretending to light themselves on fire." robyn told her that dylan had complimented her on the dress she'd worn and called her beautiful. that night, following the after party, robyn drove dylan home. the girl was his ride to and from each event.

"he was in a really great mood that night," recalls a second limo rider, monica schuster.

there is a brief scene in one of the final basement tapes where dylan speaks directly to the girl, telling her, "robyn, i didn’t really want to go to prom. but since i'm going to be dying, i thought i might do something cool."

the last time she saw dylan, robyn says, she had been heading to class after calculus when she spotted him and their mutual friend joe walking down the hall. she'd tell investigators there was "not really" anything which appeared different about him, but did mention he was "kind of quiet." additionally, she'd follow up by explaining dylan was not a morning person and it was regular for him to not be very talkative.

on april 20th, robyn had wanted to find eric so she could give him the t-shirt she got him, likely as a late gift for his eighteenth birthday which had been a little over a week prior, but never got the chance. when the shooting started, the girl had been on her way out of the building to her car to go out for lunch. she hid under a seat in her car upon hearing gunfire and stayed inside the vehicle until it stopped.

soon after the shooting, it was revealed by officials that three of guns—the shotguns and hi-point 9mm carbine—were purchased by anderson, who had turned eighteen not long beforehand.

in january of the following year, robyn gave her testimony to the house judiciary committee, sharing in her written statement, "they bought guns from three sellers. they were all private. they paid cash. there was no receipt. i was not asked any questions at all. there was no background check. all i had to do was show my driver’s license to prove that i was 18."

because she came forward and testified and did not purchase any handguns (which were unlawful for minors to purchase and posses or have given to them by someone of legal age who'd knowingly bought purchased the gun for them) for eric and dylan who'd been underage at the time, no criminal charges were filed against anderson. however, she did agree to pay $300,000 for a settlement fund that went toward the families of three dozen families.

this is the last time robyn's name was brought up in the media in the aftermath of the killings her two friends meticulously carried out.

Delusions

Dylan, unknowingly, seemed to experience quite a few delusions. But he did not view them as this (clearly). Experiencing delusions would line up mostly with bipolar 2 disorder and schizotypal personality disorder.

Dylan referred to himself in a third person standpoint. He seemingly believed he was not himself and had some out-of-body entity controlling him (in a way). Dylan also crossed out his own name once and instead wrote, "Me," as if he was not himself. He also claims multiple times that he doesn't have the same human nature as "Dylan".

"When Dylan Benet Klebold got covered up by this entity containing Dylan's body..." "I lack the true human nature that Dylan owned." (Dylan Klebold, 1997) "Does that make me a non-human? YES."

Constant thoughts of suicide

It is no secret Dylan wrote about ending his own life constantly over the span of multiple years. In fact, this is partially why people tend to ignorantly focus on him solely being suicidal.

Dylan, obviously, ended his life by a gunshot wound to the side of the head. In his journals, Dylan consistently mentions suicide in nearly every single page. His is clearly a sign that something wasn't okay.

"OOOh god I HATE my life; I want to die really bad right now." "true true I hate everything. why can't I die..." "No emotions. not caring. yet another stage in this shit life. suicide... Dylan Klebold." "Wanna die & be free w. my love... if she even exists." "If by fate's choice, [edited] didn't love me, id slit my wrist & blow-up Atlanta strapped to my neck."

Thoughts and plans of homicide prior to 4/20

Prior to Eric ever mentioning NBK or committing murder, Dylan brings up killing people dating back to 1997. In fact, it's implied he had the original plan for their attack.

Dylan directly mentions committing a mass murder dating back to 11/03/97, where he mentions obtaining a firearm and going on a killing spree. He also later mentions "going NBK" later with someone who was not Eric.

"[edited] will get me a gun, I'll go on my killing spree against anyone I want." "Soon... either ill commit suicide, or I'll get w. [edited] & it will be NBK for us." "Society is tightening its grip on me, & soon I & [edited] will snap, he will have on revenge on society." (implied)

Constantly feeling outcasted or different from other people

Dylan often discusses himself as if he's "the odd one out." He discusses feeling different from everyone else around him, as if he's displaced.

Dylan consistently discusses feeling different from most people. This actually might relate back to his belief of having a connected "spiritual entity". This trait is common in those with StPD. I've seen various schizotypal people discuss feeling almost as if they're not human because of how different they feel as if they're purely just an existence.

"People are alike, I am different - Dylan" "Yo.... whassup... heehehehe...Know what's whi wierd? Everyone knows everyone. I swear, like im an outcast," "As I see the people at school - some good, some bad - I see how different I am (aren't we all you'll say) yet I'm on such a greater scale of difference." "Nobody accepting me even though I want to be accepted."

Suspiciousness of others/a belief others are purposely conspiring against him

Dylan showed very obvious signs of paranoia and signs of distrust in other people.

Dylan discusses feeling as if others purposely treated him as if he was lesser than them. He also, somewhat, expresses this when discussing his friends.

"I don't know what I do wrong with people (mainly women) - it's like they all set out to hate & ignore me." "Everyone knows everyone. I swear, like I'm an outcast, & everyone is conspiring against me...."

Consistent feelings of abandonment and loneliness

Dylan clearly mentions multiple times he feels as if people have abandoned him and that he feels as if he has no one.

Dylan obviously had people, but he internally felt as if he did not. He even mentions girls making him feel this way despite them not even knowing him.

"The possible abandonment, persecution is not something I want to face, yet it is so primitive to me." "I'm here, STILL alone, still in pain." "All people I ever might have loved have abandoned me; my parents piss me off & hate me..." "I have no money, no happiness, no friends... Eric will be getting farther away soon... I'll have less than nothing..." "Everyone moves up I always stayed. Abandonment." "I want to die sooo bad... such a sad, desolate, lonely, unsalvageable I feel I am..... not fair, NOT FAIR!!!!" "I helped them both out thru life, & they left me in the abyss of suffering." "Ever since 7th grade, I've felt lonely..."

Delusions of grandiosity or godliness

Despite Dylan seeming self-loathing, he actually seemed to have either some sort of superiority complex or God complex.

Dylan refers to himself as God multiple times and calls himself godlike. He speaks of other people as if they're below him in every way possible, often referring to them as zombies. This is also, clearly, a sign of a delusion. These could also line up with bipolar disorder and StPD.

"The zombies & their society band together & try to destroy what is superior & what they don't understand & are afraid of." "Only for the gods though (me, [edited] & etc.)" "I am GoD. [edited] is GoD. & zombies will pay for their arrogance, hate, fear, abandonment, & distrust." "Soon we will live in the halcyons of our minds, the one thing that made me a god." "I UNDERSTAND THE EVERYTHING, I AM THE GOD OF THE EVERYTHING W. [edited]!"

Other notable signs:

Constant feelings of sadness, frustration, or anger.

Excessive usage of alcohol (to the point where it was notable to friends).

Seemingly against treatment and receiving mental health help. He denied his mother's attempts and stated on his diversion report that he did not see it as necessary.

Physically harming other people prior to the attack.

Mentions of self-harm, specifically cutting himself.

My personal takeaway (opinion):

I personally believe Dylan Klebold has StPD along with MDD or bipolar disorder. I believe Dylan had a superiority complex while also feeling constantly inferior to other people, similar to Eric's writings.

I personally believe people like Dylan are actually the ones you have to look out for over people like Eric. Eric was outwardly expressing homicidal thoughts, admitted to feeling suicidal, and expressed anger constantly (seemingly this was a cry for help). But Dylan internalized his for the most part and even refused help from people. This is why so many people were shocked Dylan was involved, not Eric. This is why so many people believed he was manipulated. Dylan hid his homicidal thoughts and suicidal tendencies well.

People tend to list traits of Dylan as if they were solely traits of him, all while Eric had the same traits. Both were deeply insecure, struggled with depression, had a temper, felt suicidal, felt homicidal, felt lonely, and felt outcasted.

Eric is seemingly framed as more violent because he expresses his ideologies more outwardly and doesn't shy away in his journals from expressing hatred. But I honestly do not believe a lot of things Eric says. This is because he knew people would read his journals (starting off sentences with somewhat of a "to whoever is reading this," sort of ordeal). Why wouldn't the guy who felt lonely and inferior his entire life try to frame himself as a psychopathic, fascist murder-machine? That would make people scared of him, not see him for what he truly was: a deeply insecure guy with anger issues who is constantly teased and bullied, leading to intense feelings of inferiority and loneliness.

Like guys, Dylan literally thought an external force kept other people from opening his journals...

Anyways, I hope this summary was okay! I can do other people if wanted!!

Sources:

Source #1

Source #2