Ethereal Warding

You elegantly move your hand over a door, inscribing upon in ghostly, ethereal writing, arcane runes to attempt to ward off spirits from breaching into a room. When you do all incorporeal undead attempting to enter the room using etherealness or a similar trait it must make a DC 17 Charisma saving throw or be repelled away from the room 10 feet as a failure. Every time a creature fails this saving throw the DC lowers by 1, if the DC reaches 1 the spell ends. If a creature succeeds on this saving throw or the spell ends the creature successfully enters the room and the runes weaken, lowering the DC by 5.

For the purposes of this spell double doors, portcullises and trapdoors count as one door. If a room has multiple doors the DC of this spell is lowered by 5 for each other entrance in the room. At any time as a free action, you may mentally choose to hide or reveal these runes. While hidden all creatures without truesight are unable to see the runes, however, the effects of this spell still take place. If the runes activate they are immediately revealed to all creatures.

At Higher Levels. When you cast this spell using a spell slot of 4th level or higher, you can target one additional door or entrance with this spell for each slot level above 3rd.