Get ready for 12 hours of rolling dice, story adventures and monster slaying. This weekend, gamers from the Vanguard Dungeons and Dragons are hosting their second annual livestream fundraiser.

Last year's event raised nearly $18,000 for Extra Life, a charity that supports the Children's Hospital of Philadelphia.

It's fantasy. It's captivating storytelling told by Vanguard Dungeons and Dragons.

Founder Shawn Kitchin took CBS News Philadelphia inside the adventures of "The Shattered Obelisk."

"First-level basic adventure," Kitchin said.

Two years ago, Kitchin started an in-person gaming community in Newark, Delaware.

"How do we get people together to play a game I really love playing?" Kitchin recalled. "'Dungeons and Dragons' is essentially a narrative role-playing game."

Their monthly meetups at Timothy's of Newark quickly took off, drawing creative minds to the table.

For those new to the game, think of it as fantasy storytelling — one player serves as the Dungeon Master, the narrator who guides the story. And that role? Kitchin has mastered it.

"I'm going to give you all the characters you're going to meet. I like doing voices," Kitchin said. "I do a bit of Scottish. It's not great."

The rest of the players roll dice to decide their characters' fates.

"As a group of adventurers and heroes, it's a perfect marriage," Kitchin said. "That's how we started the charity idea."

That idea became "Tabletop for CHOP: A Quest for Hope."

The Vanguard is taking D&D online for 12 hours straight again. Last year, they raised close to $18,000, and this year, they hope to top that.

"We decided to support this charity called Extra Life," Kitchin said. "It's all for gamers and streamers, and Extra Life itself really helps with the quality of life for what kids are going through at CHOP, whether it's never having a birthday party because they're through treatment all the time."

Here's the fun part: donors can control the game. For just $2, the dungeon master has to wear a fake mustache. For $2,000, they can cast Meteor Swarm, one of the most powerful spells in the game.

But for Kitchin, the mission runs deeper.

"It definitely changed and gave me a purpose that was so much different," Kitchin said.

Each roll is a reminder that their impact goes beyond the game.

"Stories matter," Kitchin said, "they can affect real-life change, and really help people out by just rolling some dice."

The 12-hour gaming marathon kicks off Sunday from 10 a.m. to 10 p.m. You can watch the stream on Vanguard's Twitch channel.