The actual in-game stats the Eden Group Dagger gives both greater Atk and Matk than its counterpart.
Dagger Info :http://db.irowiki.org/db/item-info/13066/
Shuriken Info:http://db.irowiki.org/db/item-info/13310/
"After completing certain Eden training quests level range (tier), you obtain a weapon based upon your class. The more a weapon is advanced in tier, the stronger it gets compared to his previous counterpart. The level requirement of the weapon also increase, but you keep all previous weapons as you progress. Certain classes have a choice at each unlocking tier, independent of their previous selections."
~http://irowiki.org/wiki/Eden_Group_Equipments_Quests