The Mystery Of Mithras

The Golden Slave, XVI.

Eodan has "...offered to many powerful gods..." (p. 213):

the Cimbrian Bull which is Moon and Sun;

the Earth Mother, Hertha/Cybele;

the Roman god, Jupiter;

a "...fork-tongued thunder-snake...," (p. 214) invoked by Tjorr.

(According to Wikipedia, "Hertha" turns out to be Nerthus.)

Despite serving the King of Pontus, Eodan cannot offer to the Pontine god, Mithras, because he has not yet "...been initiated into his mysteries." (ibid.) Mithraism is intermediate between paganism and Christianity. Conversion to the latter involves not only offering to Christ bot also no longer offering to any other gods.

Eodan understands that Mithras:

is both strong and consoling;
was "...born of a virgin through the grace of Ahura-Mazda the Good..." (ibid.);
conducts his followers to a heaven which is preferable to Hades;
has a midwinter birthday of feasts and gifts;
will lead warriors from his heaven in a last battle against Ahriman.

Eodan wonders whether Mithras can call his dead wife, Hwicca, "...back from the night wind..." (ibid.) and thinks that Northern Europeans might prefer a god like Mithras to their dark formless Powers. Yes, the Aesir, led by Odin, will invade and make alliance with the Vanir and Odin will lead dead warriors at Ragnarok.

As Everard told Denison, Zoroastrian/Mithraic ideas got into early Christianity through post-Exilic Judaism. CS Lewis re-imagined Armageddon:

"'The siege of your world will be raised, the black spot cleared away, before the real beginning. In those days Maleldil will go to war - in us, and in many who once were hnau on your world, and in many from far off and in many eldila and, last of all, in Himself unveiled, He will go down to Thulcandra. Some of us will go before. It is in my mind, Malacandra, that thou and I will be among those. We shall fall upon your moon, wherein there is a secret evil, and which is as the shield of the Dark Lord of Thulcandra - scarred with many a blow. We shall break her. Her light shall be put out. Her fragments shall fall into your world and the seas and the smoke shall arise so that the dwellers in Thulcandra will no longer see the light of Arbol. And as Maleldil himself draws near, the evil things in your world shall show themselves stripped of disguise so that plagues and horrors shall cover your lands and seas. But in the end all shall be cleansed...'"
-CS Lewis, Perelandra IN Lewis, The Cosmic Trilogy (London, 1990), pp. 145-348 AT 17, pp. 338-339.

And Aslan appears at the end of the Last Battle in Narnia. Mithras, Odin, Maleldil and Aslan are powerful myths.