Both Air and Da Capo are harem in genre. They also both deal with issues one would have to face in a high school setting. In each series the main hero is trying to find out what is going on around him and how everything impacts the main heroine, the one that he loves. He also helps the other girls that like him.
Seara and Sakura, the main characters in Da Capo and Baby Love, can not wait to grow up so that they can have the love of the one who promised it to them. In Seara's case her love comes through with the realization that she is now grown up. With Sakura, however, her love may have found his own path to take.
Kiki is a young witch who has just turned thirteen, and as tradition dictates she must now leave the safety of her home for a year to undergo witch training. One clear night, Kiki takes off with her cat Jiji and her mother's broomstick to start her new life, and finds herself in a town near the ocean - but she's disappointed to find that people aren't nearly as friendly as she'd imagined they'd be. With nowhere to stay and no outstanding magical skills besides flying, Kiki begins to wonder if she's come to the right place; but after returning a pacifier to a customer of a local shop, its owner, Osono, offers her a place to stay. Kiki soon decides that she'll start her own delivery service, and with the help of newfound friends she sets forth on a journey to discover who she is and how to make it on her own.
What is the problem with a little witch trying to learn magic on her own? Well for one she eventually stirs up some serious trouble for the people around her. This happens to both Kiki in Kiki's Delivery Service and Aisia in Da Capo; both have good intentions but neither full-fledged witch can fully manifest their powers. Both witches strive to make the people around them happy; will they succeed in their goal?
Even though Koi Kaze has a more direct incest relationship between brother and sister, the dynamic is faced in Da Capo as well, though not to such an extreme. There are excitingly dramatic moments in both series as well as an overwhelming seriousness for the characters and the trials they face.
A thousand years ago, The Dark Kingdom, led by Queen Beryl, attacked the Moon Kingdom. Utterly ravaged, Serenity, the Queen of the Moon, sent the souls of her daughter Princess Serenity, the members of her court, her lover and her guardians to Earth to be reborn. One thousand years later, the Dark Kingdom returns and begins to steal energy to wake its own dark Queen Metallia. Sensing that evil forces are nearby, Luna, a guardian of the princess, finds the bumbling and lazy Tsukino Usagi and awakens the soldier within her known as Sailor Moon. While they battle evil and search for the other sailor senshi, Sailor Moon must learn how to be brave, gain strength and search for the Moon Princess!
Both Sailor Moon and Da Capo involve magical aspects that are introduced and are both set in a high school atmosphere. They each have an undercurrent of forbidden love and a desire that those around them do not understand.