User blog comment:B214/Chapter 499: Gray & Juvia/@comment-4933386-20160829110259/@comment-84.197.239.101-20160829142228

The chain and choker breaking means nothing, since Invel was quite distressed with himself for "miscalculating". He may have caused the chain to melt, believing it was no longer needed as both were dead/dieing.

He will likely be beaten in one shot next chapter, since Mavis urgently needs to be rid of her choker.