the reason why ymir chose mikasa is because she was the one who could free her from her love from king fritz, she killed her loved one yada yada yada might be wrong from everything im saying but the death of eren and mikasa decapitating eren was actually foreshadowed in the early episodes of season1, mikasa's backstory begins with her watching a praying mantis or grasshopper? which are known for a female (praying mantis, grasshopper thing) to decapitate a male one. and this insect was shown at the opening of idk probably season2? oh and u should re-read this because isayama snuck a few different characters in this manga, (breaking bad, game of thrones, HIS EDITORS AND CREW, probably real life people and you) lots of foreshadowing happens in aot reread it rn 💕💕