I finished the Daggerfall Covenant questline playthrough on my main last night, making that two of the three factions completed in Elder Scrolls Online. While I still have another entire faction's quests to run through, I found the following interactions between factions interesting:
- Ebonheart Pact -- Attacked/invaded by Daggerfall Covenant, Attacked by strike teams of Aldmeri Dominion
- Daggerfall Covenant -- Attacked by strike teams of Aldmeri Dominion
And that's it. A slaver ship that sells slaves to House Telvanni is involved in one localized quest location, but Telvanni isn't part of the Ebonheart Pact. There's also another "spy" episode in which House Telvanni is implicated, but again the Ebonheart Pact again comes up clean when it comes to interfaction fighting in the questlines.
I have to wonder whether this observation holds up with the Aldmeri Dominion, so we'll see.
One last item of notice: High King Emeric came off as a conniving asshole in the three faction meeting that leads to the Coldharbour section of the questline, and I was willing to bet that he looked much better to a member of the Daggerfall Covenant itself. After having played through the entire Daggerfall Covenant questline, I can conclude that yes, he does come off much better in that questline, but he also still comes off as an asshole in that cross faction meeting.
Oh well. Some people never change.