>>8220318
wtf, since when was there cd in leviathan. maybe its been a bit too long since ive read it

>>8220335
The second protagonist Deryn, pretends to be a boy to stay in the army, and nobody finds out about it for 2 out of 3 novels

I haven't read Leviathan, but there's a character in Ender's Game called Tetra who's a tomboy and dresses the same as the rest of the crew of the space battle school that they're attending(which is mostly boys). There are quite a few scenes where they talk about it and mention her tomboyish attitude and dress. I don't remember much more about it since I haven't read the book in a while, and I mostly like it for nostalgic reasons. It may be to your liking OP.

In the Shadow Campaigns series there's a woman who's background is there was a failed suicide pact with her girlfriend (as I interpreted it anyways) when she was a teenager, so she ran away and disguised herself as a man and joined the army.

The series itself is fairly good, It's a "fantasy napoleonic" about not-Napoleon.

Keys to the kingdom has a cross-dressing tomboy but she has no love story and is a pretty secondary character all around.