Another wonderful episode with many interesting hidden references 🙂
Kukulkan (“Plumed Serpent”, “Feathered Serpent”) is a god in the pantheon of Maya mythology. El Castillo in Chichen Itza served as a temple to Kukulkan. During the spring and fall equinoxes the shadow cast by the angle of the sun and edges of the nine steps of the pyramid combined with the northern stairway and the stone serpent head carvings create the illusion of a massive serpent descending the pyramid.
Grave of Erin’s father
She does not want to do it, but it must be done.
Soyon: “I still have conscience.” She did it because she is refusing to support system of Touda abuse for military purposes. Chief: “Seems like I have some conscience too.” He knows that it was her, but he is not going to tell about it.
Ariyo (Pāli) a person who has thought on the four chief truths of Buddhism, a Buddhist priest. Also means noble, holy. Ariyo aṭṭhaṅgiko maggo (Pāli) – Noble Eightfold Path. Japanese equivalent is 八正道, Hasshōdō. The Noble Eightfold Path is one of the principal teachings of the Buddha, who described it as the way leading to the cessation of suffering (dukkha) and the achievement of self-awakening. It is used in Buddhist practice as a technique to develop insight into the nature of things and to eradicate greed, hatred, and delusion.
Aurora is the Latin word for dawn, the goddess of dawn in Roman mythology. Auroras, sometimes called the northern and southern (polar) lights or aurorae (singular: aurora), are natural light displays in the sky, usually observed at night, particularly in the polar regions.
Kitsune's Thoughts 
Those are really fascinating references that you caught! I’d never heard of that temple you mentioned; it sounds really amazing.
Thank you 🙂 Well, they might not be the source of inspiration for the writers, but these are the things that came to my mind when I saw the images.
The most striking part of the episode to me was Soyon’s decision to kill Kiba and face the consequences.