He has a charming, resonating voice all while he treats his work and civilians as gentle as he possibly can with as much care. A debonair individual, he is serious and diligent with his work and works tirelessly until he meets the final delivery. Although he somewhat appears intimidating during work, he tries to make friends with anyone he meets in the neighborhood during his daytime job. Matias is surprisingly friendly when one finds him in person during his delivering hours.

However, in his private life doesn't seem to be very social with anyone who interacts with him and is often treating others in a rude, negative manner. With the exception of his son, Oliver - whom he acts like a doting and playful father with just the two of them. A rare occasion is seen with his partner, where his personality often switches quickly like a light switch when he is with his beloved partner that he finds... tolerable than most people.
The Milkman often don't seem to get along with anyone who refuses the milk bottles he delivers. Nor get along with anyone who utterly hates drinking milk.

He grows an unhealthy obsession of his job as the Milkman...

Knock knock, 
it was the same every morning.

Knock knock,
everyday at a quarter to nine.

Knock knock,
he was charming, I loved his eyes.

Knock knock, 
they had such a color, and everything was fine.

Knock knock.
He'd ask to come in, the same everyday.

Knock knock.
I'd say no. Take the milk, and see him on his way.

Knock knock.
But he was funny, and finally, I invited him in.

Knock knock,
with those lovely eyes crinkled, and a devious grin.

Knock.
I didn't see anything in his hand.

Knock. 

Why would I? He was just my friend, the Milkman.

He no longer comes, to knock on my door.

No one comes by, much anymore.

Not since a scream, and a body hit the floor. 

- Credited to Sonefire @ Recolor.me 

• Matias rarely recalls any memories before he became a Milkman. Nothing about his past life, aside from very little glimpses of working in a pasture with a couple of cows that had belonged in a dairy farm.
• He knows a lot of milk facts such as: "milk is rich in nutrients essential for human health, including Vitamins A, D, and B12"
• Happily married to a very [happy man].
  > A love-hate relationship, in Matias's case. He may act like he won't enjoy Richard's company, but in fact, very much enjoys it.
• Has a child that he adopted. His name is [Oliver] and he loves him as much as Smiley.
  > Oliver loves drinking milk as much as the Milkman.
• Hates hates soy milk.
• Tolerates any form of nut milk.
• Cookies are his favorite snack.
  > Preferred cookies are Oreos. Otherwise he isn't very picky when it comes to cookies.
• Only drinks milk.
  > Once in a blue moon, he will drink water. But only when he's very much parched and there's no milk in the vicinity.
• You will not see the Milkman on Wednesdays.
  > No one delivers milk on Wednesday.
• Has a separate fridge, solely filled with milk.
  > Gets empty quite fast.
  > Very organized, and hates it when there's something else in there aside from milk.
• The company he works for is called "Mootime Dairy"
  > Never met any other Milkman in the Neighborhood.
  > In fact, he's never really met any other employee in the Mootime Dairy company, except for the one who supplies his milk. They rarely talk though.
• Matias reacts to [spoiled milk] much differently than others (NSFW).
  > Doesn't like the taste of it, but causes a different Mad Cow reaction after consuming it (refer to the link).

When he is on the hunt, he severely lacks empathy as well as mortal values. But this is only just a slight shift of his personality during his work time and he remains as serious and diligent as ever... even when he's not delivering milk. His smiles are rather devious more than it is charming; it makes others feel rather uncomfortable.

"Don't you love him? My wonderful creation. Isn't he just perfect...?"

He rarely seemed like a real person. In fact, he remained lifeless for several days until his creator deemed him complete. A man in all white, with a perfectly tied bowtie around his collar and matched his black hair. He had a rather brilliant, satisfying shade of red as the color of his eyes. But his face seemed blank, emotionless as he stared off into an endless color of white around him. He may have a bit of a scruff... but that's what give his appearance some character.

The speaker was right behind him; his hands on his creation's shoulders and squeezing them lightly. His fingers running down his jawline and down his chin.

"Matias. Matias K. Pierce is your name. Remember that, my dear."

The speaker tilted his head up, as his large thumb ran across his lips. Matias could see the same bright and lovely red eyes peering above him, as if it was a complete reflection of himself.

"I've got a perfect job for you, Matias. A diligent Milkman. To share the world of our love and destroy those who disagree."

All Matias could do was blink in response, as if he barely heard a single word.

"You wouldn't need to remember me," he continued. He reached over to the table next to him, to grab a lonely single glass of milk. He perched the rim to the Milkman's lips and the first drop had awakened him.

The taste of milk. It felt like a gift. A delicious one. Who would deny such a splendid taste?

The realization was apparent in his eyes. He knew what he needed to do.

Ability: Mad Cow
> Matias mysteriously has inhumane strength, capable for him to survive most things that humans cannot. It is a passive ability.
> Mad Cow can be triggered voluntarily but having it active will cause him become insane and completely disregards all mortal life around him. However, he is quicker than his normal stage.
> Milk only heals his wounds during the Mad Cow stage. He can sense where every single drop of milk around him.
> One could tell Mad Cow is occurring by his glowing red eyes. The Milkman has had red eyes for a long while, but no one has ever noticed them (assuming they were brown from the reflection of the sunlight).
> Only one man can trigger the Milkman's Mad Cow ability involuntarily.

Ability: Entering the [Neighborhood]
> Victims that are attempting to run away from the Milkman makes it seem rather impossible to escape from.
> A victim will end up running into an endless, unknown street, where every house will eventually become the exact same the farther they run. This means that every house will have the same structure, colors, orientation, and even the house decorations used. The only thing that is different is the house numbers. There will be no intersection to turn, and the victim(s) will eventually stop at a cul de sac. From there is self-explanatory.
> All houses in said street will have all lights off except the eerie light in the front porch. Peering inside of the house will simply be dark and no one will answer to anyone knocking. In fact, the Milkman may be the one to open the door.

• The Milkman's victims often varies. Usually those who are lactose intolerant, and especially those who refuses a bottle from him.
  > His victims often appears as a [MISSING] Victim on the side of his brand's Milk carton, just before the victim dies by his hands.
• His weapons usually switch between his hands, a knife, a broken glass bottle, or just drowning his victims by shoving their heads into a [milk pail].