Sanctum of Abjuration

A sense of calm and serenity fills the air, as everything pervading this place radiates a sense of order and precision.
The will of the caster brings an aura of permanence and protection to such a Sanctum.

Arcane wards weave protective magics that fortify the caster. They seize control of the place of power, replacing any prior masters. While they are within their Sanctum, they gain
access to the following lair actions at their first tier.

Lair Actions
On initiative count 20 (losing initiative ties), the caster can take a lair action to cause one of the following magical effects;
the caster can't use the same effect two rounds in a row:

• The spellcaster may cast the Blade Ward cantrip.The spellcaster may cast Dispel Magic at 3rd / 5th / 7th
  level without using a spell slot.
• The spellcaster may cast Banishment at 4th / 5th / 6th level without using a spell slot.
• The spellcaster may construct an Arcane Ward to protect themselves. The ward can absorb 10 / 20 / 30 damage, and recovers hit points every time they cast an abjuration spell
  of 1st level or higher equal to twice the level of the spell. If the spellcaster already has this feature from the Abjurer subclass, instead their current Arcane Ward's maximum is increased by 10 / 20 / 30 hit points, and it recovers hit points equal to four times the spell level of any abjuration spell cast.
• Using a Lair action to reinforce this ward automatically restores 10 / 20 / 30 hit points. If the Arcane Ward reaches 0 hit points, it can't absorb damage, but its magic remains.