About Ivar(If his route is open), I guess he actually doesn't care about his daughter. Regarding the fact that our MC killed his daughter, he would only think that she wasn't strong enough. At the same time, he is interested in the situation that original Palmier being betrayed by Quill and our MC being deceived into this world to replace the original Palmier , so he comes over to flirt with the protagonist...! This is my guess! Feels great!!!
p.s. I used a translator so my sentences might look a bit weird🥹