In Ghost of Sparta, when Kratos finds Deimos in the Domain of Death, he has those huge rocks detaining his hands (so they were used as handcuffs), and Kratos had to destroy one of them and break a chain to set Deimos free. Then, they talk and Deimos attacks Kratos, using the remaining rock on his right arm as a gauntlet to fight him. Ok. No problem on that, I'm sure everyone who has beaten the game already knows that. But I noticed that when Deimos attacked with it, the rock glowed with fire, like Deimos' birthmark, so it could channel his power (probably, this fire power is his rage for being abandoned by Kratos). Why would someone - in this case, Thanatos - use these rocks/gauntlets to bind Deimos if they channeled his powers so well and would be perfect for him to escape that place someday? It doesn't make sense.
I thought a lot of things and what I'm going to say now is confusing, but what if Thanatos didn't know that those rocks could channel Deimos' power, almost as if they were specially made for him? The only way he wouldn't know it would be if someone else had chosen them, not himself. And I thought again: who in God of War could make a magic weapon with fire powers specially made for Deimos, which he could use to channel his rage and finish anyone in his way without mercy? A person/god whose powers are fire, rage and battle and knows Deimos. Now I got where I wanted to get: Ares.
When Kratos and Deimos were young, Ares and Athena kidnapped Deimos in Sparta because they thought he was the Marked Warrior who would bring the end of Olympus: Ares believed Deimos was the Marked one at that time. And then he himself took him to the Domain of Death (nobody says or shows anything about Athena going there with him, only that she was with him in Sparta) and gives Deimos to Thanatos, for him to be eternally tortured. Thanatos himself said that "Ares chose poorly that day". Maybe Athena knew that Deimos wasn't the Marked Warrior, but Kratos was, but she didn't tell Ares to protect both Kratos and Olympus: if he had the wrong warrior, Olympus wouldn't be in danger. It would make sense, since she's the goddess of wisdom. This proves that Ares himself chose the child (Kratos or Deimos).
In Ascension, we see not only that Ares does have fire powers in God of War, but that he was plotting against Olympus long before Kratos and Deimos were born, and that he wanted to use the Marked Warrior to destroy Olympus and take control over the world. If he thought Deimos was this Warrior, I'm sure he would want him.
But Deimos would be of no use if he spent all eternity as a prisioner of Thanatos. Of course, he thought of that, too: he knew that if Deimos was tortured for years and no one rescued him, he would grow as an angered and vengeful person whose only desire was to have his revenge against those who abandoned him (and who wouldn't?). Zeus wanted Deimos to remain in the Domain of Death for all eternity, so he wouldn't be a threat for Olympus, but did he want Deimos to remain in the Domain of Death being tortured for all eternity? If someone said he would become the biggest enemy of Olympus one day, would it be wise to torture him and make him even more angered than before? I'm feeling Ares told Thanatos to torture him, when he should only have told him to keep him there, as Zeus actually wanted.
So Ares gives Deimos the weapon that, combined with his rage (the same rage that made his birthmark glow with fire), would be a perfect item for the escape of the Domain of Death: the Gauntlets. And he gives that to Thanatos telling him they would be perfect to bind Deimos for all eternity, so he doesn't even think on the possibility of those rocks being weapons. When Deimos finally found his way out of there (probably killing Thanatos in the process), Ares would make him believe that Olympus abandoned him, and not only Kratos (and he wouldn't be wrong, after all). And that's it. He has the perfect weapon against Olympus.
Of course, when he found out that Kratos was the true Marked Warrior, he totally forgot about Deimos to turn his attention to Kratos. That's ironic: even Ares, the only person who actually remembered of Deimos for all these years, abandoned him. So, years later, after even Ares was dead, Kratos discovers Deimos was still alive and goes after him, and we all know what happens. Maybe Ares' death made the Gauntlets weaker than they should be, because Kratos was able to break one of them and, after a few blows, the other one was gone, too.
I know it's crazy to try to deduce all of this just because a rock shines when it's on someone's hand, and anyone who read this probably thinks I am crazy, now, but what do you guys think? Just another thing that has nothing to do with all of this: wouldn't the Gauntlet(s) of Deimos be a perfect weapon for Multiplayer?