For those of you not familiar with these entities I will mostly discuss War of the Ancients and the WarCraft chronicles: volume 1. For those of you wishing to learn more I suggest this video. The WarCraft chronicles seem to indicate that the Titans are more powerful than the Old Gods and quite a lot at that. First it mentions that Aman'Thul ripped Y'Shaarj, the most powerful of the Old Gods from its seat and that created the well of eternity. This made the Titans realize that they couldn't slay the Old Gods as that would mean the doom of Azeroth and Azeroth is the egg of a Titan, so they didn't want that. Instead the Titans imprisoned the Old Gods to minimize their influence as much as possible. Second we have Sargeras who split a planet storing a titan spirit inside into two, this despite the fact that at least one Old God inhabited this planet. So you're saying, "cool, Sargeras is more powerful than the Old Gods, what of it?" Well if I were to assume the Old Gods are in fact less powerful than Sargeras then the entire storyline of WarCraft falls apart, don't believe me? Lets start at the one source we have that states the Old Gods to be VASTLY more powerful than Sargeras, the War of the Ancients. In the book trilogy the entire foundation of the story is based on the Old Gods being more powerful than Sargeras. Korialstrasz and Nozdormu both state that the Old Gods are an evil more powerful even than Sargeras. Now ask yourself who are the only living beings on Azeroth who could have had such a knowledge, the titan keepers whom themselves heard it directly from the titans. Not to mention that Alexstrasza fears the Old Gods more than Sargeras, she knows that the arrival of Sargeras will mean certain death and almost guaranteed torture, yet she fears the Old Gods more. You're thinking "but wait couldn't Sargeras have tricked everyone, I mean when Illidan saw his true power Illidan realized that what Azshara and the others had seen was but a fraction." Yes that's true but I have several complaints with that. First the chronicles quite clearly states that Sargeras knows that there's a planet called Azeroth but he has no idea where it is, how to find it or even if there are any Old Gods on it yet he's supposed to have managed to manipulate these entities whos existence he did not know of? Secondly Sargeras needed help to channel the powers of the Demon Soul, a tool so simplistic even Varo'Then, a captain who could barely wield magic managed to use it to almost kill Korialstrasz, one of the largest red dragons alive, and yet we are supposed to belive that he managed to outwit the Old Gods? Thirdly as I said, Illidan did witness the true power of Sargeras and he was under the control of the Old Gods, so if he knew the true power of Sargeras so would the Old Gods, yet they kept going with the summoning. Forth we do enter the though process of the Old Gods at some rare occasions and in War of the Ancients it quite specifically states that they don't fear Sargeras since he's just one Titan and it took several of his brethren to even imprison them, the Old Gods are quite clearly referring to the highest of the Pantheons. But what would it mean for Azeroth if I assumed that the Old Gods were weaker than Sargeras? It would mean that Sargeras was never contacted, unless you believe Azshara to be able to cast such powerful spells that it tares apart the very fabrics of time and space, and lets be realistic, she's not. It would mean that Illidan never aligned himself with the highborne, never got his eyes replaced, never became a demon hunter and that he'd still be friends with Tyrande and Malfurion. It would mean that the Dragon Soul would never have needed to exist and Neltharion might to this day not have revealed his madness. The orcs would never have invaded Azeroth, the Lich King would never have his seat in Azeroth, Kalimdor would still be one huge continent with Northrend, Eastern Kingdoms, Pandaria and all the islands as part of one huge continent. That's just some of the things that would change, in reality nothing we had would be the same. My conclusion is that the Old Gods can only be more powerful than Sargeras because otherwise all of WarCraft falls apart and that these indications we see in the chronicles are only meant to lead us astray and they hold no basis in reality.