Generally, you can take ideas from life and other games or thats what I do. Some of my funnest Ideas came from other games or life. For example, I grabbed one of my skills for my Source hero from chess. I suggested an ability in the abilities section that worked like a slingshot. After traveling backwards for sometime you were slingshoted forward. This skill came from watching a friend practice his golf swing. These skills are just a few of the ones I have gathered from my surroundings.
I bring this up because most recently I have bought the mass effect trilogy for the ps3 (I know I should have waited for ps4) anyway. I bought it and saw the galatic warp and was thinking wouldn’t it be cool if I could add that process to dota. But it was already in dota, and alot. Pitlord’s ultimate, Nature’s teleportation, and tp scroll. So I got to thinking how could I up the ante.
Then it came to me on the while driving through a storm. I had to deliver an item to school. So while there I felt like a courier. ANd was thinking what if I could just teleport the item into the hands of the people I needed to get it to. Then I started thinking about dota again. And I thought what if we had a courier that delivered purchased items to the hero after some delay. And thats the idea.
I was also thinking that it could be a spirit that revolves around the player sort krobelus’s ultimate or Io’s Spirits. That way you still see the courier. Also it probably take up an item slot not sure yet (Dota 2 not sure how it would b e implemented).