Make use of items, the most expensive potion completely refills your health.
Airmid route starts upon completing the side quest (which you can get from the guild) "Kobold in the cellar?!", continue the main storyline without getting into any other route, and upon completing the main quest "Nemesis", you will get into Airmid route.
Demeter doesn't have a real route, her scenes can be done on any route. However, her character is still lacking scenes, they'll be added in future. Only a few ones are available right now.
Viewing post in Harem route not able to beat aisha
ok i understand but that means i need a lot of elixir cause everytime i attack her with bell i miss i only hit her once with a crit as for airmid i guess means also no bordel as for the demeter one i asked cause i have not met her anymore after the side quest with the chicken thats why i asked and i still have not seen all scences that is why i asked about her
I only tested normal mode, so result may vary on hard, but you should be able to hit Aisha if you maxed your stats on every level (so 1500 before hitting level 2, then 1500 again before hitting 3, then getting 1500). Aisha is a very skilled level 3, so you need to make use of your MC's ability and always go over 999 on EACH level.
When it comes to hitting her, your character's agility needs to be over Aisha's dexterity. Hard, but not impossible.