Weapon upgrade: dark Excalibur Merric

I was a bit confused on the trailer for this an was wondering if with weapon refinery, will Merric be able to learn Dark Excalibur like Sonya?

Sonya is by far my strongest hero, she’s +spd -def and +1 merged, I even gave her swift sparrow to help her. I summoned my first Merric, 4 Star +spd -def, And was wondering if he could use dark Excalibur and sort of become a tangier sonya, the 2 of them together would be pretty interesting if I could give him bow breaker so Sonya fights green and blue mages, Merric takes the brave lyns and brave bow users with defect missile, and they both have magical wo doa weapons with moonbow.