I really like the idea
1.For something like this, it's alright - but for a full game, I'd like to see what the gameplay would be like without the Lifespan meter. If it is kept, maybe add an option to escape.
2.Maybe the Knight could block, parry and counter based on her current weapon.
3.More inventory space, using healing items outside of battles, the attack item can be used preemptively (as in, you use it and the next creature takes the hit).
Hope all goes well with this, it's fun to play and I'd really like to see the full game.