Serious question: what are souls?
It really depends on who you ask. Asking for a person’s soul concept is like asking for their god concept. The definition varies wildly according to a person’s individual belief system, and it’s usually tied to a bunch of metaphysical nonsense bought wholesale from a religion during childhood.
Generally speaking, a person will define their soul as the qualitative variable they need to balance out the equation of their own mortality.
For instance, the average American simpleton might define their soul by saying something like, “my soul is the part of me that will go to heaven when I die.” The average skeptic clinging onto dualism might say something like, “my soul is my spiritual essence separate from my body.” Atheists who practice transcendental meditation might say, “my soul is the part of me left over when my mind is silent.” Materialists flirting with Buddhism might say, “there is no soul, and yet we are reborn from nothing.” Hipsters into existential nihilism might tell you that soul is just Aretha Franklin on vinyl.
You get the point. The soul concept is basically there to cancel out whatever existential dread is built into their personal belief system.