Complex sentence: When Icarium is recruited by the Tiste Edur he assaults the Throne of Shadow, there coming into contact with the Eres'al which healed the mental damage/scarring from his wounding of Kurald Emurlahn.
Split into simpler sentences: When Icarium is recruited by the Tiste Edur he assaults the Throne of Shadow. There he comes into contact with the Eres'al who heals the mental damage/scarring from his wounding of Kurald Emurlahn.