How Do We Explain Ryne?

[Rongway]

By the end of 5.3, the WoL possesses a magic stone with the power to Call heroes from beyond the rift to aid them. There is really no reason we couldn't use it to summon Ryne to our side if we turn out to need her help.

We don't need a lore reason to explain metamechanics. Scenario Mode only lets you choose Trusts who were actually canonically present the first time you ran the dungeon. Avatars Mode lets you pick any Trust you've leveled because Avatars Mode and Trust leveling are not in-universe things. We really need to stop trying to lore explain gameplay features that are obviously just gameplay features.