amarantines:

There is no coming back from this way of thinking.

Malik really enjoys holding someone on the spot, watching two friends emotionally torture each other until they both die, unable to do anything about it. It’s not even that Jounouchi got in his way to get to Atem — he’s having a lot of fun holding onto Jounouchi’s mind, picking at all the little memories of friendship he shared with “vessel Yuugi” (Malik’s words, not mine), and twisting them to his advantage in making this death-duel more painful for them.

He loves doing this kind of thing. He’s not a nice person. The only difference between him and Yami Malik is that he’s more calm and logical, and his love for his siblings overrides his natural urge to emotionally destroy people. Even after banishing YM, these urges are a part of Malik’s dominant personality and are not realistically going to go away.

Admittedly, I laughed out loud when I got to the part The only difference between him and Yami Malik is that he’s more calm and logical-
Because this beautiful shit lord is anything but calm. He can act it but the very second something starts to not go his way, he gets angry. It starts off with a bit of growling but as things continue not to go Malik’s way, he loses his shit. He screams, he breaks things, he shoves Rishid and knocks things out of Rishid’s hands and lashes out. Malik throws a tantrum so hard core it amuses me most of the time but I can see why it gets under his skin so easily.
Everything he had was handed to him. His role in life, food, his superiority over the rest of the family and underground cult, it was all handed to him but with a forceful hand. So he has right to be angry and lash out- but he does it against all the wrong people.

As for logical, Malik isn’t that much more logical either. He knows how to be cunning but he always complicates it by wanting to stab whoever he is making deals with in the back instead of completing his end of the deal.
You can see that with all of his Rare Hunters/Ghouls. He’s made promises for most of them; returning loved ones, fame, freedom- all of which he betrayed and lied to, setting them up to be nothing but used and then discarded. 
Marik/Yami Malik doesn’t make such deals or promises because he is self reliant and believes he is fine without anyone else. He is there to kill them and remove them at face value. He does, however, torture them but the victims are always aware of his intentions.
With Malik though, you can’t trust him not to back stab you. Which is part of why it pisses me off to no end that they were all so willing to accept Malik as good and forgivable when he’s done so much shit that doesn’t warrant forgiveness at all but I still love the little asshole.