Diabolo Franco has a score to settle.

He acted as a mercenary back in World War 3, to a mysterious contractor that went by the alias 'The Woman-With-Glasses'. She gave him his gear, a never seen before high tech mantle that was malleable enough to allow Diabolo's quick combat style while providing him with protection from bullets, fire and impact.

She often sent him in missions to stop Barbatto's faction that was wrecking Europe at the time with their skeleton army.

Franco did not care about the political ramifications of a demon invading Earth and declaring Bulgaria a plane of existence independent of the physical world nor did he care that much that he was fragging skeletons.
All he cared was getting paid.

And the Woman-With-Glasses did not paid him. She gave him a burden, a technology no one had ascess to, a goal and a promise and then she dssapered. Franco only wishes to get paid, yet he keeps running in against all short of cosmic menaces on his search for his mysterious benefactor.

The people love him, they see him as some short of hero. Yet Franco is no hero. He is a killer. A mercenary.

And he wants what it's owned to him.