Fire in Greek Easter celebration is present from old times.
In fact, fires or loads of pyrotechnics producing light, heat and loud sounds can be considered and embedded in general traditions which originate from even earlier times than those of Christianity and Easter celebration. In general fire rituals connect to rituals that originate to times much older than Christianity itself.
In a different approach, fire connects to Medieval practices which related to rituals that used to be done in Western European countries mostly.
So. fire rituals in Greek Orthodox Easter celebration have nothing to do with daemons clearing.
All these expressions ( pyrotechnics, large fires in central village squares, effigies ) all relate to an loud try to drive off death, even by "fearing death to go away" or by symbolically punishing anyone that "betrays Christ".
It may be considered a violent expression, and it perhaps is. Still it is an old tradition, nowadays relating to Easter and being met in other Mediterranean countries too ( like in Italy ).
More in depth info on this is beyond my personal knowledge and perhaps is beyond the limits of this site :)
Hope these were helpful.