When the Critical Role show started in 2015, the simple but charming Dungeons & Dragons series didn’t seem to have much ambition beyond being an entertaining web show that tapped into a game millions of people around the world play. Critical Role soon found a group of dedicated, and growing, fans — more than 22,000 subscribers on Twitch and 1 million subscribers on YouTube — and decided to use their newfound platform to try charity streaming from time to time, beginning with an event for Doctors Without Borders.