I may sound rather naive in believing this idea, but I think what Spekkio said was true. Maybe he's simply the God of War. He's just ended up at the End of Time, not to say other gods don't exist there either, just not at the 'Trainstop of Time' (It kinda reminds me of a train stop.). The reason I think he gave magic to the people of Zeal, (Prometheus and the gift of fire) is because he wants some bloodshed. War is good for him, peace isn't. Obviously he knew that if Zeal never gained magic, Queen Zeal would have never have had her engineers have the skill to make the Mammon Machine. (Zeal is floating due to some magical enchantment. No enchantment can be made beyond magic, I think that can be agreed upon.) No Mammon Machine, no draining of Lavos, no conflict. And not just conflictless in 12,000 BC, but also in 600 AD. If Janus is not launched, the Mystic War is almost ruined. By having all the warships and stuff being made, it gave him pleasure/brownie points/etc.
Now, someone may ask, if he did that, why did he give Crono and the group magic to begin with? Simply put, that is good for business too. To give them magic, he gives more tools to use for killing. I know he isn't the god of the underworld, but war is war and conflict and strife seems to work in all that. But he can't exactly do it himself. If he goes and fights people (besides the small-scale battles with him and the party) then he probably won't get the kind of pleasure he would otherwise.
I think he is strong enough to take on Lavos, but if he did take on Lavos, then there would be no reason for all the strife. Crono and co. would not have their magic, they would not have went back in time beyond saving Marle and the future would have been all sunshine and smiles when they visited. Now who wants that beyond our heroes? Spekkio probably doesn't. Spekkio probably couldn't care beyond filling in his quota of war/peopledead/etc.
Unless my memory is bad and Spekkio was the god of something else.
