Sometime ago I read a manga that involved a guy who walked into the area where lay a demon. This demon had long blonde hair and was a pure blooded demon. Although this demon was very powerful, he was unable to leave the cave for he was trapped inside of what looked like crystals or ice. The only way he could possibly escape is if he feels love? or he does something very UN-demon like. Whoever enters this demon's lair is eaten by him for he is attempting to make them cry a jewel that will set him free.
The red headed boy/guy (who I first mentioned above) has red hair and glasses (he is a very gentle person) and he is to soon die, he does not want to be a bother to anyone so he asks this demon to eat him. Soon the boy/guy dies and the demon cries and is freed. He manages to revive this red headed person and then they go off to do other things.
Those are some details I remember. If this is not enough, I remember lots of the story but just not the name. So please let me know, I would sincerely appreciate the help. Thanks!
no problema 