Arcane Siphon

Your body houses a magical anomaly, a void that devours arcane essence. You are able to draw upon the scraps of power that remain to cast basic spells, but attempts to explore your own magical ability always fail as the void consumes your own power as you form it. Perhaps you had once considered yourself incapable of magic but other's spells mysteriousy failed around you, or perhaps the void awoke later in your life, robbing you of magical ability you once posessed.

Voracity

Once actived by magical energy, the anomaly inside you stymies your attempts to use magic beyond the simplest spells, but its power seeps into the spells you can still form with its energy. You may awaken it as a bonus action and it automatically awakens after you expend a spell slot. While the anomaly is awakened, you can't expend spell slots but you add your Charisma modifier to the damage you deal with any Sorcerer cantrip. It only goes dormant once you have gone 1 minute without casting a spell.

Leftovers

Even by the start of your adventures, your anomaly has already feasted upon a wide range of magical essences, the residual power of which is available to you. Whenever you gain a level in this class, you learn an additional cantrip and you may choose cantrips from the Cleric or Druid spell lists whenever you would learn a cantrip. For you, these cantrips count as Sorcerer cantrips.

Dinner for Two

At 6th level, your anomaly grows inside you and you learn a degree of control over its pull. If your void is awakened, you may cast counterspell or dispel magic at 3rd level by drawing upon it to absorb the spell or magical effect. You do not need to expend a spell slot to do so. Upon a success, the magical essence is pulled into you before your void consumes it, allowing you to cast the spell once before the end of your next turn without expending a spell slot. A spell cast in this way count as a Sorcerer spell for you, but you cannot use Metamagic on it. You may use this feature a number of times equal to your Charisma modifier and regain all expended uses after a long rest.

Extra Serving

At 14th level, your void echoes and resonates with you as you draw power from it. If you use a Metamagic option on a Sorcerer cantrip while your void is awakened, you may use an additional Metamagic option with that cantrip.

All-Consuming

At 18th level, your void's pull has suffused throughout your entire body, harmlessly absorbing even the most dangeous spells. While your void is awakened, spell attack rolls have disadvantage against you and you have advantage on saving throws against spells.

Art by Chase Stone