If one company publishes a game and another one developed it who normally keeps the rights to the game? I ask because there was a game many years ago called chaos overlords developed by a company stick man games but published by new world computing which I believe 3DO sold all the rights of to ubisoft. Basically I wonder if we'll ever see that game on here. Oh well guess I'll just have to pick up might and magic 1-6 and spend my time playing those again until it does.

I think it's decided by who created the game. If the game idea came from the developer and they shopped the game around to different publishers, then it's the devlopers. If the publisher came up with the idea and hired a developer to create it, then it's the publishers game.
I think it's that way.

It honestly doesn't matter who came up with the idea first, it is simply a matter of what rights were given to who as part of the development and distribution agreement. You could come up with the idea, but in order to get it published, you might have to negotiate away all of your rights to the intellectual property. There is no generic rule to follow, it is whatever the lawyers came up with.

Quite often a publishing deal will involve handing over all or many of these rights to the publisher. The traditional big-budget way of making games involves publisher funding from an early point, and publishers will in general not pay for the development of a game unless they get total control. It's their money, after all. The major publishers will also spend quite a lot of money marketing a game, and they don't want to create a profitable franchise for another publisher to take advantage of.
There are exceptions, of course. Smaller publishers will usually not be as demanding (but then again, they offer less, and the developers will be responsible for most of, if not all the development costs themselves), and larger developers will sometimes have the power to get better deals for themselves, even with when dealing with major publishers.
I would be surprised if 3DO didn't make sure they got all the rights to this game back when they published it. But when they went bankrupt, their rights were, as far as I can remember, sold in several packages, to several companies. So I've no idea who owns them now. Might be Ubisoft, might be someone else.

The rights originally belong to the creator/s or at least the company who the creator/s work for. For instance Miyamoto-san doesn't own the rights to Mario and Zelda, Nintendo do.
Of course Intellectual Property just like physical property can be bought, sold and swapped, in whole or in parts and that is exactly what happens all the time in the game industry. Often, especially for small developers relinquishing the rights the IP is the only way to get a publishing deal.
They can also change hands because the deal suits both parties, when Bungie wanted to split with Microsoft and become independent again they gave up the rights to Halo in order to do so. Sometimes when companies encounter financial difficulties they may sell the rights to some of the IP's they hold in order generate some income and of course when companies go bust the administrators will sell IP's in order to pay of investors and shareholders.
Actually keeping track of who owns which IP's, especially older ones is an unenviable task. I can't imagine how much leg work GOG has to go through in order to find out which party or parties they need to negotiate with in the first place in order to get some of these games here. For this I salute them. :)