 If you liked
Maga-Tsuki
|
 ...then you might like
Renai Boukun
|
Both series consists of a protagonist that are lead into a harem situation due to supernatural events that are both connected by a kiss, if there is no kiss, then death would occur (In one manga, this only occurs to the protagonist). In addition, in both harems, there is a heorine with a little sister that is in love with their older sister.