Consider Epic Martial Spiriting the Red Moon too, if you get into Lana, or just use the Blue alternative: those Red things are insanely rare in my experience.
About the Thunder Dragon, be sure to try not soloing it too: if you got units with enough health to all survive the blast, you can punish the beast and end the fight much sooner. I am also not sure what its targeting routine is: it seems awfully focused on my Altemuller for some reason, every single time.