Detect Life Energy

You detect the presence of living humanoid creatures you can or can't see. When you cast the spell or as your action during the duration, you can search for life energy within 30 feet of you. The spell can penetrate barriers, but 2 feet of rock, 2 inches of any metal other than lead, or a thin sheet of lead blocks you. You can't detect undead or constructs.

Once you detect the presence of a creature in this way, you can determine the general power level of that creature. The target must make a Wisdom saving throw. If it fails, you gain insight into the creatures challenge rating in relation to your own character level. You learn if the creature is weaker than you, much weaker, equal power, stronger than you, or much stronger. If the roll succeeds, the creature's power level remains a mystery to you.