This is the best anime I have ever seen!

In Tokyo (known as Shinto Teito in 2020, 19-year-old Minato Sahashi is extremely intelligent, but his inability to cope under pressure often results in failure.
One day, Minato meets a girl named Musubi, who literally falls from the sky. Minato soon learns that she is a Sekirei who chose him as her Ashikabi a human with special powers that allows them to have a contract with Sekirei. This binds the Sekirei to him and allows them to use their full power in elimination battles with other Sekirei. Made up of cute girls, buxom women, the Sekirei fight in a competition known as the Sekirei Plan organized by Hiroto Minaka the chairman and founder of the mysterious and powerful MBI Corp.
Minato soon learns that being the partner of a girl is not all fun and games, especially when several other Sekirei choose him as their Ashikabi each also forming a contract with him. Now Minato must find a way to survive both the life-threatening battles of the Sekirei Plan and his partners fierce competition for him.

Sekirei are superpowered beings with a different code similar to a human's. The Sekirei spaceship crashed on Earth in 1999 on Kamikura Island , and was found by two students, Hiroto Minaka and Takami Sahashi. On board the pair had found 108 life-forms described as One pillar and 107 baby birds.
The first of them a pillar, shown as #00 later renumbered and known as #01 Miya was an adult.
Eight later known as #02-09 were embryos also known as the Single Numbers.
99 others later known as #10-108 were fertilized eggs.
The adult and the eight embryos are also known as the Single Numbers. It is hinted that unwinged Single Numbers are equal or even more powerful than their winged counterparts. All of the Sekirei had used adjustments for the Sekirei Plan especially the Single Numbers. The adjustments had been used not only for making Sekirei stronger, but also for controlling and strengthening their power as only a few Ashikabi possess more than one Sekirei.

Ashikabi are humans with unique genes that enable them to empower the Sekirei destined to serve them. Through mucous contact kissing between a Sekirei and its Ashikabi a Sekirei without wings can become a winged Sekirei. Unlike Sekirei who are mostly buxom women or handsome young men, Ashikabi can be quite innocuous as they can appear in any gender, age, and even status. In the series, the power of an Ashikabi can be determined not only by the number of Sekirei he or she has in his or her disposal, but by the bond between them. As the Sekirei fight escalates, five Ashikabi in particular ascend as the favourites to win the Sekirei Fight, each having winged at least three Sekirei. One of them is Natsuo Ichinomi, the leader of the Disciplinary Squad, while each one of the four others control a different area in the city; Minato Sahashi from the North, Hayato Mikogami from the South, Izumi Higa from the East and Nishi Sanada of the West.