I understand completely what you mean, however I wouldn't instantly discount building something from an engine as being uncreative. Most modern games today are built from another engine, heck practically everything is made in the Unreal III engine (okay, well not everything). All an engine does is lay down the basics such as graphics, networking and some basic game mechanics. It's just there to save time, not to give you a template you can carbon copy and add a few quests to.
If, however, you're wanting to make your own game from scratch you need to first pick a language. C++ seems to be a good choice, I would go with managed C++ (i.e. C++.NET) rather than unmanaged though. C# is also quite a good choice as it's quick and easy to use, with much of the benefits of C++. If you're wanting to make a browser based game you could look into Java (RuneScape is coded in this) which is also quite easy to use.
After picking a language you'll first of all need to know how to make an RPG before you try to make an ORPG. The main thing to focus on learning is graphics. DirectX is powerful yet not exactly easy to use, for .NET languages SDL.NET is quite easy and great for 2D graphics involving sprites and the like. There are a few other graphics libraries out there to use (OpenGL for instance) so I'd just search about for which one is the best for what you're trying to do.
After that you'll need to look at networking, input, and sound. Once you've got all that you'll probably also have gained a working knowledge in the language you're working with, which you also need to create the mechanics of your game.
Well, that's pretty much it.
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