Blade of Io

The weapon you are holding is imbued with arcane power and guides your strikes, provided the weapon doesn't have the two handed or heavy properties.

For the duration, you can use your spellcasting ability instead of strength for the attack and damage rolls of melee attacks using that weapon. The weapon also becomes magical, if it isn't already. In addition, the weapon's damage dice becomes d8. If you weapon's damage dice is already d8, then you may increase it to d10 if you have a strength of 12 or higher. If your weapon's damage dice is already d10 (such as for a versatile longsword held with both hands), then you may increase it to d12 if you have a strength score of 14 or higher. 

The spell ends if you cast it again or if you let go of the weapon.