So much about the Shadow Isles remains unknown
https://i.imgur.com/H8G98G8.jpg
The Runeterra map has created more questions about the Shadow Isles than it has managed to answer. Even after four major lore updates, the place is still as inscrutable as ever.
Not only do we know nothing of the Ruined King's fallen kingdom, but the Blessed Isles themselves are still shrouded in mystery. The Isles were, apparently, always surrounded by white mist that kept travellers at bay, which meant that they didn't need soldiers to protect them. Their architecture had a unique look to it, and their most important buildings were repositories of knowledge, like the Hall of Conjunction or the Athenaeum of Light.
https://i.imgur.com/XxqtlQe.jpg https://i.imgur.com/Kv3C4cW.jpg
Their land was naturally magical, like Ionia, while their society was magic-oriented. They hoarded information, artifacts and secrets. The name of their capital city, Helia, the Hall of Conjunction, and the Celestial Vault all reference the sun, moon and stars, which either means that they were capable independent astrologers or somehow linked to Targon and its Aspects. The magics of the Isles were so powerful that they broke the boundary between life and death, trapping the land in a deathless state for eternity.
There're also these things: https://i.imgur.com/uMr2dUp.jpg
One of the undead creatures in the front row has an inhuman, arachnoid appearance (spawn of Vilemaw?). The cyclopean behemoth in the background has tentacles coming from its back. Are these reanimated beasts, corrupted Voidborn, or something else?
So much related to the Shadow Isles is lost or hidden; there's more to learn about the place.