How does The Last Guardian relate to Shadow of The Colossus and Ico?

I know Shadow of The Colossus is a prequel to Ico, probably set hundreds if not, thousands of years before Ico. And that what the Shaman says to Wander about him having to atone for his sins through time etc.. Hence the ongoing children with Horns. Trico, has similar horns... I m not sure if it s just another way Wander s spirit just morphed over time. Any ideas, suggestions?

Note: I finished all three games already.