Superior Cross
Summary
The demon queen subdued enormous and powerful monsters and slaughtered over half of the world's population. Surviving members of the human race elected a hero to slay the demon queen, beseeching release from her oppressive rule. However, he questions his mission to eradicate the monsters: in his opinion, they too are conscious and alive, and so he anguishes over that fact. Sheila the Demon Queen became interested in him and joined his journey, hiding her identity and with the plan to kill him after she has gained his trust. Eventually, she realizes that she fell in love with the hero, and hence their journey begins...
Continuation of the manga "Superior".
... and the second season of the Anime did a better job of pacing than I thought they would. I think they moved the Elf village arc from before hostilities with the Principality began to the inter-war period, aka the start of the second season, and used that to pad it out. Good call if that's what they did. In any event. Good season.