By using Call of the Archfiend, you can discard The Fabled Ganashia in order to Special Summon 1 level 5 or higher Fiend-type monster from your Graveyard. The Fabled Ganashia will thus be Special Summoned to the Field as well.
How to Discard
Fabled monster such as The Fabled Ganashia, unlike Dark World monsters, will activate his effect even when discarded as a cost. This makes them useful in more situations as they can give you value out of your discard costs, potentially turning them into pluses in card advantage. The Fabled Ganashia in particular revives himself as a decent beater after he is discarded. Here are some cards that can help you discard The Fabled Ganashia.