Soulshine is a heavy armor set. The 5-piece set bonus adds 450 Spell Damage to your cast time and channeled abilities.
Soulshine is part of the base game and drops in Reaper's March in the Overland content. You can also find it on Guild Traders. Each set item is bound on equip. You can acquire light armor, jewelry and weapons for this set in the Khajiit motif style.