So after the events of 3, DK wanted to play god a little so that he can make others suffer, so he time travelled by an unknown way and killed all the Smash kids' parents(Ness Lucas ETC), Mario knew the plan, so he sent a message to the past warning about DK, however he killed Ness' parents undirectly so that people would doubt it was his fault, and when he came back to the present this happened.

Ness:

I never knew my real parents...
I was told by my caretakers that before I was born, my father passed away, after a lengthy battle with lung cancer.
It was only a week before the date of my birth.
My mother had an extremely difficult delivery, and she died only one day after my birth.
Even though I never knew my parents, I miss them with all my heart.
I never got to know their voices, their lullabies, their touch or their love.
I grew up in the supervision of a foster home, with many other children my age, sometimes they'd pick on me, and hurt my feelings.
My caretakers would not offer much support, as they seemed not to understand.
The only comfort I found in my empty life... was Donkey Kong.
His games brought joy to my day, and his merchandise brought material value to my life.
On the day of my 12th birthday, I woke up, slipped on my DKC2 T-shirt and walked downstairs.
The other children gathered to mock me as usual, they pointed fingers mocking me for the fact that I had no friends outside of the orphanage to come to my birthday party.
"You don't have any friends" began the blonde kid who looks a bit similar to me "other than Donkey Kong of course"
The children laughed.
Even an idiot like you should know that DK is decay.
I didn't eat eat cake, play games or laugh with my pals, I simply went upstairs and wrote in my diary "May 18th" I wrote in the corner of the page, I've been surrounded by people all day, but I've never felt more alone.
I put the pen down and closed the book.
I took a deep breath and was surprised to find my lungs filling with the scent of... coconuts...
I heard a soft fatherly voice from the window of the room "You were never alone" said the voice.
Not now, not ever, I turned my head around and spotted a looming brown figure.
"Do-Donkey Kong" I whispered "is that you?"
Why, it is, I came for your birthday, boy.
My heart grows, a smile crossed my face "Really? thank you DK!"
"This is the happiest day of my life!" I told in... elated.
"Come with me, you're present is downstairs." he said.
I hopped up, took DK's hand, and rushed down the stairs.
The children all looked at DK and I as we entered the room.
What could the present be I wondered, I was so excited!
DK winked at me before crouching down and putting out his arms beside him, T posing.
He began a cold spring towards the group of children and dwelled his arms to clothesline every single one of them.
I could hear the snapping of necks and the satisfying wheezes of the air being knocked out of the lunges of the children.
DK smiled and picked up the surviving children (Lucas and Villager) until he had them all in his grasp.
With his free hand he stretched his d**g and let hi C, pungent d**k spring into the crisp air.
With one overhand king of swing, he impaled ALL of the children on his d**k and effortlessly.
He f**ked all of their corpses until he finished, with torrent of steaming coconut milk.
No words were exchanged, my body, writhing with desire seemed to read his mind.
He looked me in the eye and with an instant, I knew what I had to do.
I give to my basic primal urges, and lunged and DK's still ekonged coconut gun.
Grunting and leaning down, I expose my pale cheeks to the kong. and let him fill me.
Inch by inch I was claimed.
I bit my lips and began to cry, as pain, pleasure, and love consumed my soul.

Soon, DK filled my bowels with another flash flood of jungly fluid.
He slipped me off his penis, and carried me to bed.
I was exhausted, but satisfied.
Donkey Kong tucked me in, kissed my forehead, and headed for the window.
"Wait, Donkey Kong!" I said. "Stay with me, please. I want you to be my Daddy." DK chuckled and smiled.
"I am your Father, boy, for all who truly believe in Donkey Kong are my children."
DK winked before hopping out of the window into the crisp night air. I close my eyes as I think of my last thought before drifting to sleep.
DK... is... love... DK... is... life...