Because she wasn't on the random sketch that inspired the game.
Kamidori really is nothing like Fire Emblem in terms of strategy, it's *apparently* like the uh, that one JRPG series with crafting (this is from hearsay can you tell). If you want strategy Sengoku Rance is probably the best thing but the story, characters and entire setting are ridiculously sex focused so it's obviously not suitable for a VN newbie.
G Senjou is a good next step, followed by Ever17, mostly because G Senjou has a decent translation, rather quick pacing outside of the side routes (Don't play those unless you specifically like the girl involved) and when it really gets going you quickly get caught up in it.
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You're messing with me! You're messing with me, aren't you!?
You're making fun of me, aren't you!? Aren't you!? You definitely are! I'll murder you!