I personally think that Zeref should've had a demon who wanted to die just as much as he did, or even moreso simply for the comedy of it all.
Hell make Larcade, Zeref's best and damn near most perfect demonic creation aside from Natsu, have Zeref's lust for the sweet release of death.
Imagine Zeref at the forefront of his hoard of demonic entities, preparing for hopefully the final battle to end it all- the one that does him in and hopefully brings his demise- and Larcade just slides up to him and does this












