Experimentum Cavum

Being born a Hollow, a cursed existence whose mind has been eroded, your sanity fleeting, a certain Reaper has taken you in as a test subject for various experiments however. 
Elevated to the position of a proper sentient being, you traveled the Twilight, grew stronger, learnt what it means to live, and faced many obstacles in the process. 
Your very past existence being one of them, it all has only strengthened you however, never being truly lost.

At the start of combat, you may form a spectral Hollowed Mask by expending 5 sorcery points, which lasts for 1 hour or until you decide to dismiss it.

While you have this mask on your body, you can fuel it with sorcery points once per turn, granting you the following benefits.

Being of Two: Your arcane geometry has been enhanced, for the cost of 2 sorcery points you may target yourself and an additional creature that is within your glyph with a spell that has a range of self up to 8th level.

Being both a Hollow, the source of your magic, as well as your own person, a personality that is willing to do good, your magic appears to split. Accomodating for both your desires of assisting others, as well as personal strength.

Scapegoat's Mask: Your barrier has been enhanced, for the cost of 1 sorcery point, creatures that have temporary hit points from your "Arcane Swell; Barrier" have the next instance of damage they take reduced by a number of dice the size of your Archon Die equal to your charisma modifier.

Yet, despite that desire for personal strength, that Hollow side of yours is still willing to protect others, taking the hit should it be necessary. Just as it sacrificed itself to protect your lover, risking destruction in the process, it now offers up a fragment of its vitality to shield those around you.

Essence Consumption: For the cost of 3 sorcery points, you may sacrifice 300 hit points of a willing creature within one of your glyphs and feed your mask, you then roll one of your archon die and recover spell slots of a combined level equal to the result rolled. (For example on a roll of 6, you may regain a 6th level slot or two 3rd level slots.)

Alas, a Hollow still needs to feed in order to maintain itself. Devouring the health of those that offer themselves to it, it savors the moment of recovery.

Drawback: At the end of a round, if you fail to feed the mask 5 sorcery points in order to maintain it, you lose access to your spellcasting feature for 1 hour, as the mask seals your magic away and feeds on it instead.

However, it is not always possible to keep the Hollow's hunger at bay, and should it grow too intense, you may just lose access to the power it provides you with until it is sated.