Board Thread:Lore Discussion/@comment-6702118-20140722142914/@comment-9212235-20150503171015

It's from multiple stories, altmer is most prominent in it. The Heart of Lorkhan was shot to the other side of Tamriel, its blood spraying everywhere. Some of it landed in an Ayleid well, crystalized, and was then cut into a diamond by Ayleids. This diamond was then given to Alesh and it was claimed to be blood from Akatosh. Why is that? Well because Akatosh is partially Lorkhan's Heart.

This can be seen also in C0DA where Akatosh is inside Lorkhan's chest before it closes up, reunited with its lost Heart.

Keep in mind, Akatosh as the Heart is far more symbolic than literal. He's not the physical object seen in Morrowind.