Why does Miquella help us?

As said by Ranni at the beginning, she gives us the spectral wolves and says that the previous owner (possibly Miquella) wanted to give them to us, not only that, but somehow The torrent that was in Miquella's hands ended up with Melina, who handed it to us knowing that we would make better use of it.. Did Miquella know all this time that we would be the tainted one who defeated Radahn? But how, if there are several other ones who were coming to the lands between, too (like Roderika)? And why would Ranni give the wolves as if she was sure the Elden Lord would be a random like us? I can not understand.

As said by Ranni at the beginning, she gives us the spectral wolves and says that the previous owner (possibly Miquella) wanted to give them to us, not only that, but somehow The torrent that was in Miquella's hands ended up with Melina, who handed it to us knowing that we would make better use of it.. Did Miquella know all this time that we would be the tainted one who defeated Radahn? But how, if there are several other ones who were coming to the lands between, too (like Roderika)? And why would Ranni give the wolves as if she was sure the Elden Lord would be a random like us? I can not understand.