[quote=@Rawk]
<Snipped quote by Grec>

Hmm. Well it's not my call as I'm not the GM, but unless your Lasombra has adapted Thaumaturgy ("blood magic") to augment his Obtenebration discipline, causing impaled vamps to "evaporate into mist" doesn't generally happen in the WoD mechanics. 

I do think we need to agree how death is handled.

Perhaps [@ezekiel] can shed some light?
[/quote]

When vampires suffer their final death they evaporate into red mist. Or at least in the Bloodlines games they do. 

[url]https://youtu.be/QjkfTiVNEuY?t=11m53s[/url]