Fan made halo games?

Hey, this is more of a question than a creation, but I didn’t really know where to post this in the forums so here goes.

Hypothetically speaking, if a halo fan made a 100% free halo game with 100% original assets would there be any legal implications? (like using the halo name/logo)? There seems to be quite a lot of Halo CE mods that are pretty awesome, but they’re just that, mods. I’m talking about a full, fan made, 100% free game. I remember a small 2D game called “Halo:Zero” which was before Halo CE and it was pretty cool. If I’m not mistaken it had bungie’s approval and special thanks on the credits.

I’d like to know this, because I don’t want to get sued by anyone regarding any future experiments I might (or might not) make. I’m currently taking a post-grad course in illustration and animation and I’ve been really curious about game development too.

Well that’s about it, thanks for reading!
Cheers