I think he died because of part of his destiny. Can shinigami interfere with matters of life and death? I thought he would be cursed by Ankhseram because it disrupts the cycle of life and death. I mean shinigami only directs the soul and shouldn't interfere with the cycle of life and death
I hope Gildarts gets to know Cana is his kid early on since even though he seems to be an irresponsible womaniser, he deserves to be part of her life as a parent
He really should tell people that his magic is a mix between a summons and equip magic, that way he can explain why he has a sword with a spirit within it with knowledge of another power/magic/spirit system