Creating a Fan made game based off Halo.


So myself and my team have been wanting to create a Fan made game within the Halo universe and I thought it would be wise to know the risks and if such a project would be doable within 343 Industries blessing. I know this type of project would be a long a perilous journey however I plan to create all assets (Weapons, Vehicles, Scenery, Objects, etc) from scratch so that no models have been ripped from the game or another 3D artist outside my team.

So the real question to ask is if I may be able to continue my efforts and start creating this Fan made game without the risk of being asked not to or done for copyright, etc, and if i need to take anything into consideration and know the risks

Thanks for reading, hope i receive some useful info.