Species: Secret God
Ability: Capable of creating doors on the back of anything
A hidden god who lurks behind all things in creation.
She has a wide range of public faces-- an Earth mother goddess, a god of noh, a god of stars, a god of silkworm breeding, a god of impediments, a god of burakumin, et cetera.
Nobody knows what her true nature really is.
She's the ultimate secret god, whose true form must never be seen, heard, or spoken of.
Her status as a "secret god" doesn't mean she's hidden or anything, though.
At times, she makes ostentatious public appearances to show off her grand presence.
She claims that her objective was to find successors for Satono and Mai, but if she ended up unable to find any suitable successors, she'd be fine making the two servants continue to work for her.
Her true goal was to stand out.
To make a big show of herself, and engrave herself into the memories of every human, youkai, and sage in Gensokyo.
It seems she didn't find any successor servants in the end, but it appears that her latter goal was well and truly achieved.
She is also one of the sages who created the Gensokyo of today.
She protects Gensokyo from the outside world, can move anywhere she likes, and at some point without realizing it at first, she gained a mysterious power to control both vitality and mental energy, which she uses for her duty of keeping Gensokyo's balance intact.
Her menial tasks are usually entrusted to her two douji servants that wait upon her (ie. Satono and Mai).
She shows no mercy to those who act rudely to her, and grants blessings to those who treat her with reverence.
Fearsome as an enemy and reliable as an ally, she's the classic example of a god.
The seasons on our heroines' backs were a trap that Okina had arranged.
Our protagonist used Okina's season trap to her own advantage, and challenged her for a rematch.
At this, the ultimate secret god agreed to refrain from chasing the protagonist off with the seasons' magic power, and revealed her true form.
It was a chaotic fusion of many gods' forms, every bit the same as the face she shows publicly.
Speaking of which, she may be a "secret god," but she's not hiding anything.
From the very beginning, she was a secret god who put everything she has out in plain sight.