Gray watchers are witches that stand astride the gates between life and death. Equal parts healers and killers, they are masters of positive and negative energy alike. No mere necromancers, they are still willing to and capable of treating with, controlling, or destroying the undead, and often do all three in equal measure.
When you select this archetype at 2nd level, your familiar's type changes to undead, it gains immunity to cold and necrotic damage and resistance to fire, lightning, thunder, and acid damage and damage from non-magical weapons. Its attacks also deal necrotic damage, and once per long rest it can cast Speak with Dead on your behalf at 3rd level. It appears as a ghostly, spectral version of your chosen animal. You also learn the chill touch and spare the dying cantrips if you do not know them already.
Starting at 6th level, if an undead creature wishes to attack you or cast a harmful spell against you, it must first make a wisdom save against your spell save DC. On a failure it must choose a different target for its attack or the attack is wasted. An undead that is not mindless is aware of this ability before it tries to attack. If you attack an undead creature, cast a spell targeting it, or cause it to take damage, you lose this protection against that undead creature for the next 24 hours.
At 10th level you gain resistance to necrotic and radiant damage, your hit point maximum cannot be reduced, and whenever you are healed by a spell it heals you an additional amount equal to the spell level. In addition, if you would damage an undead creature with a spell or ability that deals necrotic damage, you may instead choose to heal it for the same amount.
At 14th level you always have the resurrection spell prepared, it does not count against your number of prepared spells, and once per long rest you may cast it without expending a spell slot. In addition, if a creature has been dead less than a year, you may cast this spell to raise them without requiring a material component. Once you have raised a particular creature this way you may not raise that same creature in this way again, and doing so is exhausting, inflicting penalties as if the target has been dead for over 1 year.