Luka Sabbat was in attendance for Mase's party. 1
The Grown-ish star, who was rumored to be dating Kourtney, was at the party and went to town on the piñata with Mason.
Like every Kardashian kid, Mason got a custom-made Fortnite cake. 2
Some of these cakes the Kardashian kids get almost look too pretty to eat.
There were, of course, other themed treats aside from the cake. 3
There were cake pops, cookies and mini ice cream cones decorating the dessert table. If it's one thing they do well, it's throw a party.
Of course she had to pose for a pic with Kanye. 5
Uncle Ye was in attendance to celebrate his nephew's birthday, so of course, the DJ had to strike a pose and take a pic with the rapper. "Chicago’s very own," she captioned the snap.
There were huge TV screens all throughout the backyard. 6
To go along with the them, there were even TVs and comfy chairs set up for the kids to play the video game during the party.
But no need to worry, the kids still got out on the dance floor. 7
Thanks to the talented DJ Livia, the boys left their video games aside and hit the dance floor to show off their cool moves. It's great to see kids step away from technology and let loose a little bit.
The entire backyard was transformed into a birthday wonderland. 8
The chic outdoor area of Kourtney's house was transformed into a Fortnite wonderland--but even the adults had areas to enjoy!
Kourtney sang "Happy Birthday" to her little boy. 9
He was surrounded by his friends as his mom and the rest of his family wished him a happy birthday. Look at that custom-made hat!
Reign was living it up during the party. 11
Reign might've already had his own Tarzan-themed birthday celebration a few weeks ago, but he also had himself a good time at his big brother's party. Two parties are better than one!
Mason's aunties were also in attendance. 12
Khloé Kardashian, Kylie and Kendall Jenner were all the party and having some fun on the dance floor. Khloé brought her little baby, True, and Kylie brought daughter Stormi, who was in her aunt Kendall's arms.
Mason's West cousins were also at the party. 13
While they didn't appear in many of the other videos, his cousin North West was standing right behind him while he was getting ready to blow the candles. Diddy's adorable twin daughters, Jessie James Combs and D'Lila Star Combs, were also there.
Baby True was ready to party. 14
Little True was all smiles and dressed in all pink for her cousin's big party.
Kourt showed off her mom's look on Instagram. 15
Kris is no average grandmother. She showed up to the kid's party wearing a Burberry jacket and matching beret, like the true boss she is.
Even the entrance of the house was decorated. 16
Khloé shared a video of the entrance of the house and a path was lined with horse piñatas from the video game. Attention to detail is key.