HMS Nelson in Celes's costume, chained? [Kancolle x FF6] (Patreon)

"Do you think that you can chain me like this?"

HMS Nelson, cosplaying as Celes Chere, is chained in the underground jail. 

But she doesn't mind at all.

"You can't escape! That chain is made by mythril!" said the imperial soldier. 

"Mythril?! lol"

...Was mythril so hard material in FF6?