Shaar HaGilgulim, a kabbalistic work, identifies two different types of souls and elaborates on them: souls that possess the nature of Abel and souls that possess the nature of Cain.
This is not a division between good souls and evil souls, for this source attributes the nature of Cain to the souls of many great Torah leaders.
Rather, the division is one of character. The souls with the nature of Abel are milder and more pleasant, whereas those with the nature of Cain are stronger and more creative.
This distinction becomes apparent when one considers the Torah’s portrayals of Adam’s sons, Cain and Seth, and their descendants.
Cain is remembered primarily for killing his brother Abel, but we are also told something else about him: He is the first person to build.
Indeed, while Adam lived for many centuries and possessed abundant wisdom, Cain is the one who built the first city.
–Rabbi Adin Steinsaltz
From Talks on the Parasha