Ostara, also known as Ēostre, is a Germanic goddess of the Spring Equinox. There is debate as to whether she was really worshiped, with some scholars attesting that she was an invention of Saint Bede, an English Monk whose 8th-century treatise The Reckoning of Time, is the sole historical source of Ostara. Whatever the case, as noted by Mr. Wednesday, all it takes for a god to be born is for them to collect faithful followers.
For the modern Ostara, in her flowing floral dress and Easter bonnet, the beliefs of old that used to nourish her had to blend with more modern sensibilities to keep her going. In theology, the blending of multiple religious belief systems to form a new one is known as "religious syncretism". We have already seen this in American Gods with Vulcan, and it is the compromise the new gods offered to Mr. Wednesday, which he turned down. Now, he wants Ostara on his side for the war, and he isn’t above lying to her about the fate of Vulcan to get her on his side. He flatters her with stories of her immense strength and how it could return to her if she joined in his plan: To wake up an apathetic population to their existence and force them into worship.
Before the battle can commence, Ostara has to deal with a few more gate-crashers. Laura Moon (Emily Browning), now more decomposed than ever, has arrived with Mad Sweeney (Pablo Schreiber) in tow, seeking Shadow and a solution to her small death problem. Ostara can return life to those who seek it, but unfortunately, Laura's fate is beyond her abilities. She informs Laura that she cannot be fixed as she was killed by a god, and even other gods cannot meddle in those affairs.
More gate-crashers turn up (as informed to Ostara by her helper bunny), and Media (Gillian Anderson), dressed as Judy Garland in Easter Parade, drops by. This is where the dealings between the gods of old and new become clearer, as it is revealed that Ostara also took the compromise offered and latched onto Christianity and non-theistic celebrations to reclaim her relevance.
This isn’t a totally happy deal, as Ostara feels she has been “misrepresented in the media” to the point where nobody even knows her name. She is celebrated, but with no real dedication or understanding, it’s just not the same, and Mr. Wednesday is only too happy to play into those vulnerabilities. He believes he can offer her, and all the Old Gods, a return to the good old days, but they must be willing to demand it, and cause a little pain in the process.
Mr. Wednesday calls up his powers of thunder and lightning to make a sacrifice to Ostara, toasting the New Gods’ faceless goons, finally revealing his true nature to Shadow as the Norse god Odin. Empowered, Ostara shows exactly what she’s capable of, summoning the sunrise before taking back the life she gave to Spring. All around her, trees lose their greenery, the grass turns gray, and crops shrivel into dust. The war has been declared: If humanity wants Spring back, they’d best start praying for it to the Queen herself.
Viewers will have to wait a while for the second season to see how the epic war plays out, and show-runners Fuller and Michael Green have promised characters like Ostara and Bilquis will play more prominent roles in the series than they do in the book (in terms of how much the show has covered so far, we’re about a third of the way through the novel).
For now, the diminutive Ostara has provided the ultimate wake-up call to the Old Gods and a world that forgot them, so American Gods has much to give us in the coming years, because now, both sides of the battle have a Queen on their side.