User blog comment:Miskos3/Fairy Tail 544: You're the King, Review/@comment-4933386-20170714090726/@comment-4449950-20170714232545

From my understanding, Meredy linked to Lucy, whose feelings of love for others allowed her to connect to said others, whose feelings allowed her to then connect to even more "others", until you have the whole continent connected linked like some giant web with everyone feeding the link into others they love and care about.

And, I mean, at this stage we can expect asspulls, but given that we haven't seen what Meredy can do since her first appearance and it's been over 8 years (7 year time skip + Avatar 1 year) I think it's one of the more plausible asspulls of the series .-. You could also argue that everyone fuelled the link with their own Magic which is why it didn't seem to drain Meredy to connect so many people. Just my take though.