From MangaHelpers:

Mikado Shuuji is just an ordinary guy, but he has a very unusual knife that he uses for cooking. It's actually a famous short sword that marks its owner as the head of the ninjas, and now there are hot ninja girls coming after him to take it back. Hinamori Botan is one of those hot ninja girls, but her efforts to attack Shuuji mostly end up inadvertently stripping her. After she concludes that she does not want to steal the sword and kill Shuuji, she ends up deciding to serve him as a ninja instead. Now she must protect him from the other ninja that come to claim his sword and his life!

After an accident our protagonist Amagami Kouichi becomes involved with Itanami-san a well known beauty of his school and secretly a vampire.

The spin-off manga centers on the character Kotori Otonashi, an office clerk at 765 Production, during her high school days.

These are different stories involving Devilman's world. Some are about Devilman and add to the mythology some are separate stories that don't involve Devilman but take place the same time as the events in the original Devilman manga. They are illustrated by various artists. There are some color pages in the start middle and toward the end. There are some truly amazing art and stories in these volumes.

Number one is written and illustrated by Lazy Hagawari, Tatsuya Egawa, Katsuya Terada, Ken Ishikawa, Go Nagai and Shinichi Hiromoto.

Number two is written and illustrated by Hitoshi Iwaaki, Noriko Nagano, Go Nagai, Akihiko Takadera and Kazuko Yumeno.

Number three is written and illustrated by Noburu Miyama, Miki Toro, Shinobu Kaze, Sho-u Tajima, Masaomi Kanzaki, Yoshikazu Yasuhiko and Iou Kuroda.

The master spy codenamed has spent his days on undercover missions, all for the dream of a better world. But one day, he receives a particularly difficult new order from command. For his mission, he must form a temporary family and start a new life?! A Spy/Action/Comedy about a one-of-a-kind family!

(Source: Manga PLUS)

The manga is based on THE iDOLM@STER music rhythm game, in which the player guides nine idol singers as their producer.
(Source: MU)

Tsurugi Tatsuno is a boy who competes in Virtual Digimon Battle tournaments. When a Kuwagamon appeared in the Real World, his Greymon came to life and protected him. Tsurugi is summoned to the Digital World by Piximon to save the Digital World from the evil Barbamon. Since his Digimon has a hexagon shape on him, it's an Illegal Digimon, meaning that Digimon bearing such symbols can help save the Digital World. Tsurugi's Greymon later De-Digivolves to Agumon and they meet other characters destined to save the Digital World from the forces of Barbamon. Now they must stop Barbamon and his minions before they get all the DigiMemories and take over both worlds.