Yamagishi, Hokuto

Long ago in a distant land, when the heavens ruled the earth, the two of them met by a trick of destiny...

Called the "Wise man of the woods" and given much respect by the villagers, messenger of heaven Olgrius is searching for the origin of the incessant outbreak of storms. Then a villager, speaking riddles of an attacking beast, appears.

The being that Olgrius sees when he returns to the scene of the crime is a savage beast fallen from heaven. But the beast differs from the rumors—he touches Olgrius gently, and protects him from danger...!? 

(Source: Nakama)

Wild Wind

Sasaki, Kumiko

Fantasy series of short stories that involves animals:

Pet Doctor Atsushi Kirishima meets a cat-guy with tail, cat-ear and injured eye when he is searching for his runaway patient animal. Atsushi can not leave the cat-guy and takes the guy to his animal hospital with him.

Hattori, an apprentice of Atsushi's father, Kenzou finds a dog in the mountains and brings it back in a car. On the way home the dog changes into a girl..

(from B-U)

Suzu no Ne ga Kikoeru

鈴の音がきこえる

Kamei, Yogorouta

At the end of the yearly winter, when the Tetsugome Zorainu (or "Celestial Dog") is to chose its bride, all the girls are hidden within their house, afraid that they might be chosen.Yuzu, a young boy living in a household of all girls, is made the black sheep of the family and sent out to do the chores. A chance encounter by the lake with Shuro, a fox spirit, bind Yuzu and Shuro together. (Source: MangaUpdates)

Includes three one-shots: Kotonoha, Neko Yanagi, Shirotakes Bookmark

Kitsune no Tama Yobai

狐の魂呼い

Sugimoto, Ami

The third series in the "Animal X" timeline.

Having burned enough bridges in Japan, Yuuji and Minato have moved their new family to a small dinosaur-crazy town in Canada. If there's any place in the world left for Dinosauroids, surely it must be here: a town revived by the discovery of dinosaur bones, with one of the largest paleontology research centers in the world, and a network of "Conservation Centers" set up to cater to the newly-discovered Dinosauroid community. The rest of the world, None-the-wiser for the incident at the Biodome (which was covered up completely) has pretty much forgotten all about Dinosauroids.

Animal X: Genshi Sairai

Animal X―原始再来

Hiiro, Reiichi

Ayase kai almost drowns in the ocean but is saved by a merman. He thought it is all a bizare dream, until the merman shows up again at his company, this time with legs. He claims to be a rich prince and Ayase's new boss but thats not all, his true goal is to make Ayase his mate!
(from B-U)

Wild Fish

ワイルドフィッシュ

Yamato, Nase

A collection of four stories.

1. Magical Travel Boy (ch1-3): an alien boy with magical powers becomes lost while on a school excursion to planet Earth. A local street magician takes him in, but he has a dangerous secret of his own.

2. Love Hospital (ch4): a chatty student is sent to hospital with a broken leg. The patient in the adjacent bed is a student as well, yet refuses to talk to anyone at all.

3. Suki de Warui ka!! [Wrong to Like You!!] (ch5): a shy high school student is a closet otaku who loves drawing manga based on his favorite shows. One day he is horrified when another student happens to see the artwork in his notebook.

4. Foul na Kankei (ch6)

(from B-U)

Magical★Travel Boy

マジカル★トラベルBOY

Higashizato, Kirico

Kai receives a mysterious gift, a virtual reality machine that allows its users to engage in role playing in any fantasy world the mind can dream of. Any experience can be had in the virtual world--love, lust, and even sexual gratification. (Source: DramaQueen)

Invoke

The first series in the "Animal X" timeline.

27-year-old Ayukawa Yuuji has never been much of a man; he's more comfortable sewing than fighting, he faints at the sight of blood, and his fiancee is tougher than he is. He's also a terrible pushover. So when his boss at the medical lab volunteers him for some experimental drug therapy, how can he possibly refuse? All's mediocre for Yuuji: master of the pathetic.

Mediocre, that is, until a juvenile mass murder suspect jumps out from under Yuuji's bed, declaring him his "mate." Before Yuuji has time to argue, the stranger transforms into a 16 foot-tall dinosaur and beheads his roommate...

Yuuji suddenly finds himself the sole target of a lost race that turns into dinosaurs, an extremely scary woman with a Goddess-Complex, the yakuza, a mad scientist and one 17 year-old boy who really really really wants to sleep with him.

(Source: Doki-Doki)

Animal X: Aragami no Ichizoku

Animal X―荒神の一族

Mikage, Tsubaki

The merman Sango couldn’t help but falling in love with President Minami, who had implicit trust in him. However, not only did they have a huge status difference, they were different in species! To make things worse, mer-people must not lie… unless they wanted to be turned into bubbles…
(from Fantasy Shrine)

Junketsu Ningyo

The Pure Merman

純潔人魚

Sadahiro, Mika

The sequel Christmas episode after Pathos vol.1. The good old days when three guys can live happy together. At the dormitory, Ace encounters his elder student who resembles Jay very much. Ace makes love with him but...
(from B-U)

Pathos dj - EX

Kasumi, Ryouwa

Kousuke has a guardian spirit named Sakura who tries to help him with his crush on the reserved Haruno. They may have help from an unexpected ally, Haruno's guardian spirit, Yuri.

(Source: MU)

12 Manga Like Achira Kochira de Aimashou