In certain comic arcs, Mighty Thor does meet his demise. However, comic storylines can be complex and sometimes characters are brought back or their deaths have significant plot implications.
In the origin story, Thor is a powerful Asgardian. He is the son of Odin, the All - Father. Thor is known for his great strength and his mighty hammer, Mjolnir, which is a symbol of his power.
The 'mighty thor graphic novel' could be centered around Thor's adventures. It may depict his use of the mighty Mjolnir, his encounters with giants and other threats to Asgard. It may also show his growth as a character, from a brash god to a more responsible and wiser one.
One key event is Thor's banishment to Earth by Odin. Another is his discovery of how to be worthy again to wield Mjolnir. Also, his initial clash with the Frost Giants is important.