Kami nomi zo Shiru Sekai, Yamada-kun to 7-nin no Majo Recommendations
A guy (an otaku and a yankee respectively) who has never being with a girl have to go kissing every single girl he finds. The plot for TWGOK godesses arc and Yamada are the same. In TWGOK he has to kiss the girls in hir classroom to find who are the 6 goddesses while in Yamada he has to kiss the girls in his school to find the 7 witches.
Although the beginning of these two manga vary greatly, but during the process they were very similar. The male lead has some power and they both have to uses a kiss to make things work. They're both similar series involving many girls to be in love with the male lead.
Conquests takes on an unusual from in both series. While the main male protagonist are on difficult levels in terms of intellect from both series, they do have skills in finding girls with unique personas/gifts. They accomplish their conquests by initiating kisses but the process often takes tricks, strategy, and risks for the setup. There is a decent amount of comedy in both series with minimal fan service. If you're looking for story arcs crafted with supernatural themes, check out both series.
(a bit of harem but not really harem) romance- one definite end
has supernatural parts mixed into the romance story