Diloggun and Ifa are related oracles from one Yoruba source, but they are not the same practice wearing different props. Ifa is cast by a babalawo, a priest initiated to the orisha Orunmila, using a chain of eight nut shells or a tray of palm nuts manipulated to produce one of two hundred fifty six signs directly. Diloggun is cast by santeros and santeras, priests and priestesses initiated to any orisha, throwing sixteen cowrie shells and counting how many land mouth up.
Bascom, whose 1980 study Sixteen Cowries remains the standard scholarly comparison of the two systems, records that most of the sixteen parent signs share a name across both traditions, evidence of their common origin. Eji Oko is one of the exceptions: its Diloggun name, used when exactly two shells land open, does not correspond to a same-named parent figure in the Ifa corpus the way most of the other fifteen do.
Bascom names it alongside Ejila Shebora, the twelve-mouth sign, and the non-corpus zero-mouth throw called Opira, as the three points where Cuban Lucumi practice built its own vocabulary rather than carrying the Yoruba one across unchanged. That divergence is a fact about the history and structure of the two oracles, not an opening onto what Eji Oko says to the person for whom it is cast; that content is transmitted only within initiatory lineages and is withheld here accordingly.