Mercus's anthro form cannot exist in the same universe as his feral form. In both forms, he can control metal through telekinesis. The metal pictured in this art is a special alloy made by elves that is extremely pliable to his telekinesis and expands and contracts exponentially. He uses it to for weapons of all shapes and sizes while fighting, forming it seamlessly with his mind mid combat. Mercus keeps this alloy by his side at all times, either floating around under mind control or stored in a convenient tail bag he usually wears.

Art by one of my favs   squeaky_jasper