The only use for mirror in the last 2 years was in some cydra decks to trigger the skill. Until players realised that they cant relly on a trap card that needs to survive a whole turn to be useful. Stay away.
There was while a bit of mirror wall in KoG list in DLM for Fire king and it's just in recent months. Not that the card is great it's just wall of D has zero use in Legend or any KoG deck.