In the history of Tarot, until Waite changed that card, the trickser is Arcanum I - knowadays called the Magician, originally il Bagatto, le Bateleur - aka the Mountebank or Trickster. But the Fool as the "initiator-trickster" also has a history - a more mythological type of trickster, and far more worrying than the fairground trickster-Magician.
In mythology, the Fool might be related to Loki (Norse), Anansi (West African- Akan), Eshu (Yoruba), Fudugazi (Zulu), Baubo (Greek), Bes (Egyptian). There are many others. The Fool lives outside of society, he walks between worlds, and that gives him both an advantage in what he can say and do, and a disadvantage, as he is an outsider. He also represents thresholds - and indeed, in Yoruba mythology, Eshu is both the guardian of thresholds and crossroads whom we must all honour as we cross a threshold (e.g. stepping inside or outside our front door) or reach a crossroad in our lives, and the trickster who delivers necessary, sometimes cruel, sometimes gentle and funny, lessons to humans.