I'm in the same position as Dom. Shadow Dragon was the first, and as of now only, FE game I beat. While Ive started Blazing Blade and Echoes, I still look on Shadow Dragon in a very positive light, probably because I had no other experience with the series.
I just beat Shadow Dragon a few days back and decided to look into the worst possible ending. It involves:
Killing Caeda, as well as slaughyering Tiki without recruiting her
Max 15 total characters at various points throughout the game
Two characters dying before the prologue ends
Not killing...