I like comics.
It was the next logical step.
What he/she/it said.
Also to practice by drawing often and hopefully getting some feedback.
With Horizon? Well, the name and setting have been in my head for about a year now... My sister came up with the name, though :D
First it was a comic of mine, then a fantasy novel planned to be written by my sister (she's a journalist and a historian, cool dude if I may say so) and co-idea -ed & illustrated by me, then I made a RPG out of it and now's the second attempt of a comic. The story and characters have changed a bit every time, but the visual settings and overall feel to it have remained.