Shadow Magic

In contrast to other types of sorcery, shadow magic isn't usually carried in a bloodline. Instead, it represents the stain of haunted and accursed places in the world, as well as the undead and fiends that stalk them. Those who are conceived or born in such a place, or to parents who narrowly survived a traumatic encounter with creatures of the night, may have a shadowy taint upon their body and soul. Also like wild magic, it may manifest within someone on the brink of death, if they and not their parents are the one harrowed by a fell monster. However, just as other kinds of sorcery can sometimes arise spontaneously, shadow magic does have a chance of passing on to one's children.
Shadow Magic is a sorcerer subclass from XGtE. It functions as printed, except as noted below.

Shadow Magic

You know Minor Illusion as a bonus cantrip. At certain class levels, you add to your spells known from the list below. Unlike the other spells you know, these bonus spells cannot be retrained. This doesn't impede you from retraining spells you learn normally from leveling up as a sorcerer.
1st / Ray of Sickness, Silent Image
3rd / Darkness, Blindness / Deafness
5th / Fear, Phantom Steed
7th / Blight, Dimension Door
9th / Enervation, Seeming

Spells Known

You learn spells from the Sorcerer and Warlock spell lists.

Hound of Ill Omen

The hound adds your proficiency bonus to AC, to attack rolls, and to saving throws and ability checks in which it is proficient, and its temporary hit points refresh at the start of your turn each round, so it keeps up a little better at higher levels.