Saladin afterwards was able to move about Earth and have interactions with people and still basked in Light. Eris was sealed away in a Hive fortress amongst the literal monsters that killed her friends, having to use the Darkness just to survive, which brings her extreme suffering, and in that time learned all about the Hive, inside and out. Additionally, as has been pointed out, they come from different times and different circumstances, as well as different personalities. It would be difficult for them to interact.