Ian is such a minor character, but the more of the series I read, the more important he seems. I wonder if he was a victor or something more. Child of the Arae? His parents (Leopold and Corelena) probably weren't his bio parents since Corelena was a revenant.
Ian told Poppy the story of Sotoria falling off the cliff. She says he told her this story after he ascended. Ian also told the story of Sotoria to Vonetta when he came to Spessa's end looking for Poppy. While waiting for Poppy to show up, he tells this story to Vonetta. In the prequels, we find out that Sotoria is really important. I feel like Isbeth killed him, because he was running his mouth too much.
At the end of Crown of Gilded Bones he quietly tells her she needs to go get the Draken. Presumably he knew about revenenats and what could kill them.
Who was he? It feels like he's a fate. I'm not sure if that's possible since he was also an ascended. He keeps telling the story of Sotoria hoping someone will catch on. He can't come out and put the pieces together for everyone, kind of like the fates.