No end, but you can bite za dusto after 1 year of gameplay. In the options part of the sleep menu it'll be available. Doing so resets all relationships back to 0 and each 2hu's stats back to default. All kids go poof. Any 2hu you had at lover(Not love, need to have confessed to or be confessed to by them) can be fully customized at this point, allowing you to add and remove traits to them. 2hu's at love only can have a few stats upped to 2 max. Your skills and items are kept(up to 99 max per item), however if you want, you can completely sacrifice a max skill back to 0 for a permanent increase to tsp(Which normally maxes out at 4k).One question, does that game has an "end"? Like certain days or certain character affection?
EratohoK is about conquest so...
One thing for new players to know is some 2hus provide permanent benefits you can't get anywhere else. Try becoming friends with momiji and beating her in danmaku for example.