Vergil was walking through the woods after a bet from Dante to investigate the disappearances of a lot of teenage girls, do to some strange entity with no face and was rather skinny. He came to a giant red thing in the middle of the woods and pulled a piece of paper off of it, the message 1 of 8 pages appearing in front of his face.
"The hell?! And what's with this weird, random red thing, anyway. And what does this page say, 'leave me alone'? Should've thought of that before he killed a bunch of random girls." He thought to himself, continuing until he found a weird, creepy tree with another not on it. "Can't run? I'm Vergil, son of the legendary Dark Knight, Sparda! I run from nothing." He said, then heard some creepy music behind him.
Background music: Slender theme song
He continued as his normal pace, just slightly creeped out, until he came to a giant brick cross once again in the middle of the woods. "Oh, yes, it's one of those giant cross brick walls you always see in wooden areas. Honestly, this is getting REALLY random. Honestly, I thought this was going to be more exciting. Listening to Dante's one-liners is more exciting than this." Vergil said, shuttering at the fact he said that, collecting a 3 page. He then came to a large area of gas tanks. "Oh, yeah, this is getting more believable. Someone was really rushed when they designed this place." He criticized again, now collecting the 4th page and hearing loud, dramatic noises everywhere.
He continued on to find a truck and some form of shed, then collected another page from that, then he continued into the woods and found a large boulder, which also had a note on it. After he collected that, he heard something that sounded like angry growling and turned to see a very slender man with no face and tentacles coming from his back. He looked at the monster for a second, not sure how to react to it, then he pulled out his sword and sliced its head off cleanly. "Well, that was a lot easier than I expected. Lady could've done this without breaking a sweat. Dante better have a good excuse for wasting my time like this." He said walking off.
Reasons for the outcome:
1: Slender man isn't shown to be very spectacular, all he's really capable of is killing scared teenage girls, messing up cameras, starting fires and having tentacles. Vergil is shown to do a lot of incredible things, such as effortlessly vivisecting Beowulf or easily slicing off one of mutated Arkham's arms.
2: Slender man isn't very strong, shown were people can escape his grasp when he grabs their arm, where as if Vergil grabbed you, you wouldn't get away unless he let you, or your arm was slippery.
3: Vergil's got a soul-stealing sword that cuts through anything and knows how to fight, whereas Slender man sneaks up on people and kills them and they presumably have no combat experience, so we could assume that he doesn't know how to fight very well.