Relic and Class Mod
--The relic will, the mod won't. Witch (and Fox) mods only affect elemental DoT effects; the relics affect any source of elemental damage. I haven't seen Cloud Kill actually inflict "corrode" on anything, so it actually can't interact with Witch mods (which is somewhat strange for a "gamechanger" skill).
Thats a good question. IMO this article is a stub. There is basic information but not much more than you get from the game. Even the above seems misinformed since, on the video, there seems to be DOT. 16:06, December 16, 2013 (UTC)