It hasn't occurred to me until now that I don't know whether or not they were married or if elementals even have any thing equivalent to marriage.

Other things of note:

Shadow's dad was the youngest son and child of the current high king of the darkness elementals. He was also the crown prince until he gave birth to Shadow after which he was sent to the wastelands between the planes in exile. During the attack on Shadow's family, held their attackers at bay while the rest of them fled to the human realms for safety. It is unclear whether or not he survived but chances are slim that he is still alive.

Shadow's mother was the eldest daughter if the current high king of the light elementals. It is unclear what drove her to seek out Shadow's father after he had been exiled but it was great enough for her to be rather reckless in her  flight. She ended up severely injuring herself just before finding him but she had gotten close enough to where they were living for them see her get hurt. They nursed her back to health and soon afterwards she became pregnant and gave birth to Shadow's sister. During the attack on his family, she helped the two of them reach the human realms and cross over. Due to her pure blood status and high rank, however, she could not join them and after Shadow had carried his sister to safety, he turned around just in time for him to see his mother be killed by thier pursuers.

...........

Speaking habits

The more stressed out he gets the more polite and archaic his speech gets.