Who is Michael 'Bear' Kupchek from The Midnight Club and what is their importance?

Michael is Stef's partner, as well as one of his closest friends. Stef depends on Mike to help him avoid the dark depression that threatens to overcome him. Mike assists Stef in his investigation into the death of St.-Germain's body double. When he receives important information, he calls Stef to tell him he has a meeting set up with his informant and wants to meet Stef at his apartment afterward. Unfortunately, the informant is a police officerHowever, the informant turns out to be a cop who shoots and kills Mike without hesitation.