Mario

Mario is the titular protagonist of the SuperMarioLogan series. He is the owner of the main setting of the series, a house in a neighborhood (to which Black Yoshi thinks that he is in charge of the house). He, in contrast to the other characters, can solve problems rationally. When any character gives him a hard time, he is easily provoked. He appears in numerous episodes throughout SuperMarioLogan's channel. He is in love with Princess Peach, regardless of her negative attitude towards him. His love for the princess is so strong that he is defensive towards her (sometimes aggressively). Out of all the characters, Mario is the smartest and least retarded chraracter.

Black Yoshi
He and Black Yoshi started out as enemies when Black Yoshi moved in and was rude and annoying to everyone. Later Black Yoshi accidentally kills Peach and got Mario arrested for it. Mario proved himself innocent and kicked him out of the house. Bowser came created Peach zombie. Black Yoshi ditched him, only to come back with a gun and shoot the fake Peach. "Mario, you can never say I didn't do anything for you, I just saved your life! Now Bowser, its your turn!" Black Yoshi said before Bowser tricks him and stabs him in the back with a lightsaber. His death was one of the saddest for Mario, other than Mama Luigi's, over the others In the shorts and movies.

Mama Luigi
While Mario thought that Mama Luigi was retarded, He was Mario's favorite friend. This is because of all of the wacky and crazy adventures they had in the series of Mario & Luigi's Stupid & Dumb Adventures. Luigi was stupid and nonsensical, and loved Mario, and vice-versa. This is why his death was the saddest death in MLSDA.

Luigi
Luigi is Mario's brother. While they don't hang out with each other a lot, and he isn't in many episodes, they are still good friends and brothers.

Toad
Mario, like everyone else, hates toad because he's annoying, stupid and thinks he's cool. (Again, same as everyone else) Toad even got Mario arrested, when Mario was beating up Black Yoshi for killing Peach.

Shrek
Mario sorta dislikes shrek and is often annoyed at him due to his constant begging to get more cheesecake. But in the early videos, Mario was seen hanging out with shrek.

Bowser
Mario hates Bowser. He hates Bowser because he's always kidnapping Peach. Mario also hates bowser because he killed Mama Luigi, Luigi and Peach in Mario and Luigi's stupid and dumb adventures. In Mario and Bowser's Crazy and Stupid adventures, like the title suggests, Mario pairs up with Bowser to find who kidnapped peach (and Charleyyy without Mario knowing). They don't like the fact that their working together, however the duo do work together to come up with great ideas like torturing sonic to get answers.

Peach
Mario used to like peach. He was married to Peach for a long time. However, when Peach got pregnant, she started yelling and being rude to Mario. Despite this, Mario still loved however. However, when Peach found out that Mario was bald, Peach got a divorce with Mario and he was heartbroken. Mario still liked peach and wanted to remarry her. When Mario found out that Peach was pregnant with sonic's baby, Mario hated Peach. In Mario and Bowser's Creazy and Stupid Adventures, Mario wanted to save peach and hope that she will love him again. When he saves her, Peach tells mario that if she saves her baby, she will love him forever. When Mario and Bowser save her baby, Mario finds out that Peach likes Mario as a brother and tells Mario that they can start their relationship over and then get married. It is unknown if Mario still likes Peach

Bowser Jr.
Mario met Bowser Jr. once. But it is known that mario hates Jr. because he kidnapped Peach in MBCSA.