For very long, there have been only two (2) campaigns in the Wesnoth add-ons server that follow the “shadowmcanon” established by Invasion from the Unknown and After the Storm; the campaigns in question are Invasion from the Unknown, and After the Storm. Yes. That’s it. The only other campaign whose author has consulted plot matters with me and followed the shadowmcanon correctly (as opposed to blindly extrapolating from IftU and AtS and making grossly wrong assumptions about things that are left unspecified or presented in a deliberately vague fashion) is The Silver Lands, but it was abandoned far too early during its development cycle.
But the status quo has just changed with the release of version 0.5.0 of Shadows of Deception (NX-RPG), a campaign by vultraz for Wesnoth 1.11.6 and later. So far, six scenarios out of the first set of 12 have been done; the goal is two episodes.
Of note is the fact that vultraz has been a member of my After the Storm internal playtesting and prose reviewing team for a couple of years.
Per the description found in the campaign’s forum thread, Shadows of Deception (SoD for short) is “a half-RPG, half regular style Wesnoth campaign, incorporating several custom gameplay elements as well as your typical battle scenarios”. What does half-RPG mean? Damn if I know — I don't even know what a full RPG would be. Having playtested SoD prior to the release myself, though, I can say that the campaign places a fair amount of emphasis on the story while experimenting with some unusual gameplay mechanics.