Origin
Legba meets Ragman while he is pondering a recent murder victim he discovered and battled with an evil essence. Legba is a spiritualist who was drawn by Ragman’s magic suit made of rags and souls.
Creation
Legba first appears in Ragman: Cry of the Dead #1 – Mother Drum created by Elaine Lee and Gabriel Morrissette
Powers & Abilities
Legba is an old man with spiritual training, he is able to hear spirits/souls and as such can hear the thoughts of others (or at least Ragman as Ragman is thinking and Legba seems to know what he is thinking when they first meet).
It is never truly said but Legba may be the Voodoo God of the same name, in human form rather than just the old man. It is hinted at in the story but no direction confirmation is given.