You shouldn't play any of Arktwend and Myar Aranath just because of the story. They are mostly good as new-lands mods, with rather reasonable balancing and impressive-for-the-time scripting; the story of Arktwend, however, is pretty much nonsense (the mod is unfinished, since Oblivion came out before it was completely done) and the story of Myar Aranath is rather generic. Honestly there is not much to tie in together.