You have been burdened by an ancient arcane knowledge that threatens to overwhelm you. This grants you new abilities and ways of manipulating the Weave, expanding your mental ability and understanding how to combine your spell slots into more potent fonts of magical ability. You gain the following abilities:

Netherese Knowledge

Choose one of the following skills: Arcana, Investigation, Medicine, Nature, Religion, or Survival. If you lack proficiency in the chosen skill, you gain proficiency in it, and if you already have proficiency in it, you gain Expertise in it.

When you make a D20 Test for any Intelligence-based skill check, if you roll a result of a 20 on the D20, you automatically succeed and gain Heroic Inspiration. If you roll a result of a 1 on the D20, you automatically fail and you take Psychic damage equal to your bonus in the skill you were rolling a D20 Test for, which cannot be ignored or reduced in any way.

Spellcraft Manipulation

You may use a bonus action to expend one spell slot and add it's level to the level of the next spell you cast before your next turn, to a maximum combined level 10. When you combine spell slots in this way, you take Psychic damage equal to twice the combined spell level, which cannot be ignored or reduced in any way. You may upcast your spells normally and still combine it with another spell slot. If you don't cast another spell before your next turn, the slot expended by this ability remains expended.

You may use this feature a number of times equal to your proficiency bonus and regain all uses after you complete a Long Rest.