How to make a hero equip only 1 kind of item

[steelknight999]

like for example an artifact is a sword but when you get another sword your previous sword will be dropped and you will get your new sword much like mansion murderer when you're picking a weapon.

 

[DD_legionTN]

Set the equipped item into variable, and if the unit acquires an item which is a type of artifact(sword as you mentioned), Order the unit to drop the item which set into the variable and set the variable to newly acquires item.

 

[Nichilus]

Depends on what you want - do you want to prevent unit from having the same item-type more than once or prevent it from having same item class? (e.g. weapon x armor x usables, etc.)?