Frosts of Stygia

You learn to call on the infinite cold depths of Stygia to serve your commands. You gain the following benefits:

• Choose any one Ability Score and increase the score by 1, to a maximum of 20.
• When you roll cold damage for a spell you cast, you can reroll any roll of 1 on the cold damage dice, but you must use the new roll, even if it is another 1.
• Whenever you cast a spell that deals cold damage, you can summon a vortex of snow to swirl around you until the end of your next turn. The snow don’t harm you or your possessions, and partially obscures you from enemies. While the snow is present, any creature that tries to attack you with a ranged attack does with disadvantage, and any creature within 5 feet of you that hits you with a melee attack takes 1d4 cold damage.