Hey Lucas, You put a lot of movement in the spine which is good, but you have the spine cutting into the ribcage in both of these drawings. Remember, the thorasic spine curves with the back of the ribcage, yours is not. Think about what the spine is doing from a side view, that will help figure out whats happening. I did a quick sketch over your drawings to show you what I mean, I hope it helps :)

For the actual blade of the dagger you want to get a straight skinny longer line on it so it isn’t so big and smushed. More like this, so you can make the dagger more 3D if you want to.