Material-S's and Material-L's devices are not Raising Heart and Bardiche. S's is called Luciferion, and L's is called Vulfinicus. So there.

Oops! I fumbled! It's Vulnificus, not Vulfinicus.

So what's the story behind these doppelgangers?

I'm afraid I don't know. My Japanese is limited to kanas.

While I do not know Japanese, I do know the story behind them. They're part of the Book of Darkness' Automatic Defense System, apparently, along with Material-D.