Sanguine Sanctum

4th-level abjuration (Sanguimancy)
Casting Time: 1 action
Range: Self (15-foot radius hemisphere)
Components: V, S, M (Blood)
Duration: Concentration, up to 1 hour

You gather all the blood of the battlefield and create a 15-foot radius, see-through dome of crystallized blood around and above you that remains stationary for the duration of the spell, so long as you do not move. The dome can be damaged, and it has a number of hit points equal to 4d10 + your level.

Ranged attacks made from outside of the dome against creatures inside of it are made at disadvantage, whilst ranged attacks made from inside the spell’s area are made normally. Creatures can enter and exit the dome freely. Spells that would target a creature or the area inside of the dome hit the dome instead. No more than 10 creatures can fit inside of the dome. If the dome takes an amount of damage higher than its current number of hit points, the excess damage carries over to you.

Amplify(X): Choose X creatures, all other creatures treat the area within the dome as difficult terrain.

At Higher Levels: When you cast this spell using a spell slot of 5th level or higher, the dome’s base hit point value increases by 10 for each slot level above 4th.