guardian spirit
A protective spirit that watches over a person, place, or group. Common in spiritual and religious contexts.
He believes he is protected by a guardian spirit.
守護霊 is a protective guardian spirit that watches over a person, the opposite of the harmful 悪霊.
Compound of 守護 (protection) and 霊 (spirit). The exact historical origin is uncertain, but it is a modern term used in spiritual contexts.