Here's a little run-down:
Prometheus = titan, extremely WISE, because he can see the future...as in, EVERYTHING that will EVER happen. EVER. He considers the gods unjust, so he gives fire to man, even though he KNOWS what will happen to him.
He gets chained to a rock, and every day a vulture pecks out his eyes and eats his liver, which re-grow by the next day.
Loki = god of mischief and trickery, EVIL beyond belief, but a LOT like Milton's version of Lucifer (better to reign in Hell than to serve in Heaven; gods are tyrants that prevent free will; yada yada), causes the death of Balder, everyone's favourite in Asgaard.
He gets chained to a rock, and a poisonous snake drips its acidic venom in his eyes, day in and day out. His beloved wife tries to catch the venom in a bowl, to keep it from Loki's face, but she has to stop periodically to empty the bowl. Thus, he still gets poisoned-burned.