While trying to protect a wooden relic, high school student Yuuri Mito summons the Goddess Kikuramikami no Hime in the form of a sweet, affectionate child; she begins to live with him, taking the name Mashiro. Yuuri promises to marry her when she grows up, which unfortunately for him happens overnight! However, they soon have bigger things to worry about, as the relic is accidentally destroyed, unleashing the Tayutai, a human-hating race of monsters. Along with Yuuri's childhood friend Ameri, his step-sister Yumina and Mifuyu - an honour student at Flawless Girls' Acadmy - Yuuri and Mashiro must step up to fight the Tayutai, protect the world, and even learn about underwear!
Morisato Keiichi has always had bad luck. No matter what he does or how he acts, nothing seems to go his way. His bike frequently breaks down, his classmates take advantage of him, women ignore and scorn him, and on top of all that, he’s only 5'3". In Heaven, when someone’s bad luck and good luck are so heavily out of balance, Belldandy (Goddess First Class, Second Category, Unlimited) of the Goddess Assistance Agency comes to the rescue. Belldandy grants Keiichi one wish to make up for all of his bad luck, but when Keiichi wishes for Belldandy to stay by his side forever... the trouble begins. Can Keiichi keep Belldandy by his side, or will outside elements force her to return to heaven?
It's fairly easy to see the similarities between ah! my goddess and tayutama. Both revolve around a guy meeting a spiritual being in the form of an attractive female, which creates a forbidden romance scenario. So if you liked Ah! my goddess and you want to see something similar, try out tayutama -kiss on my deity- and vise versa.