I liked it!
A few things i liked were: No invincible worldending super powers. And genuine (at least perceived that way) weaknesses. You've got the half demon angle working, and the big weakness for that is it can be that time of the month for mike. What are his benefits from that though? Fire breath? Super strength? Or is it just enhanced senses and a poor temper? That would be fine too though. You just need to establish that, maybe in the third chapter, quick action scene maybe? Just a little taste of what makes him different. I did like that he carries a gun, however he should know what kind of gun it is. Anyone who carries a concealed weapon on them, knows what they're packing. Besides, if he doesn't know what caliber it is how does he buy ammo for it? Go to a gun website, or a gun store, and drool over the shiny tools of death, then pick one that fits your idea of your character.
For instance: I have a human character, in my novel, who uses two 1911 Colt .45's that were his grandfather's when he was in WWII. It fits my character, because he is big, loud, strong, and reliable, all qualities of the 1911.
(By the way his name is also Micheal)
What is Mike?
Keep up the good work!