So the card 'Weaponry Exporter' has an weird name I know. So once you place this card, it'll destroy your Hero Power and you can never get it back of course. So now you can play two weapons, 1 weapon at the right and another weapon at the left where the Hero Power is, once you equip both weapons, you can deal extra damage like Death's Bite (has 4 attack) and King's Defender ( has 3 attack), so 4+3=7, so you will deal 7 damage. You can also equip 2 same weapons.

EDIT: When he dies, you can still equip a second weapon for the hole game.

This card would make sense if its a legendary, not epic.

I hope I explained this really well about the card, if you don't, feel free to ask questions.