WARNING: The following contains spoilers for American Gods Season 3, Episode 2, "Serious Moonlight," which aired Sunday on Starz.
Throughout the past two seasons of American Gods, Mr. Wednesday, a.k.a. Odin, has been planning a war against the New Gods, recruiting deities from across the country to help in his fight. Season 3 sees the Norse god continue his mission, turning to an old friend for help.
At a dentist office, Dr. Tyrrell bargains with a kid, telling him he'll pay him twice as much as the tooth fairy will for his tooth. Right off the back, it's clear this man is likely not human given his peculiar interest in teeth; however, any doubts are thrown out the window once audiences see his office, which is full of Norse artifacts, like battle axes, helmets, swords, knives and wolf totems. With Wednesday close behind, the two reminiscent over their past together, like when they fought side by side during the Battle of Yorktown.
It is then revealed that the dentist is actually Tyr the Warlord. He is another war god from the Norse pantheon, specifically dealing with upholding justice. In some myths, he is on a similar level as Thor, and like Wednesday, his is immortalized in the contemporary world with Tuesday being connected to his namesake.
One of his most famous myths, which is retold in Neil Gaiman's Norse Mythology, is about how he lost his hand to the wolf Fenrir in service of the other gods. This seems to be acknowledged in American Gods, with Tyr having a prosthetic hand, as well as the wolf totems.
As a god, his peculiar interest in teeth makes some sense, especially since he's collecting them in a box. Gods, like Wednesday, have shown multiple times that offerings and sacrifices make them more powerful and relevant. While these teeth are not traditional offerings, they are "gifts" from humans, so this could be how Tyr has stayed relevant during these trying times for the Old Gods.
It appears Tyr is still loyal to the Old Gods, specifically the Allfather, donating a generous amount of money to the war, pledging anything for the cause, even though -- as far as audiences are aware -- these two have not discussed the details about Wednesday's war. He then swears to fight by Odin's side, even if it leads to their deaths.
Tyr is not the only god or deity to join in Wednesday's war this episode. During Zorya's funeral, he pledges to avenge her death, inviting anyone to join his crusade in restoring the honor of the true gods. It appears most of the guest are behind Wednesday after his speech, including Czernobog and Tyr, who's also attending the funeral.
Based on the Neil Gaiman novel of the same name, American Gods stars Ricky Whittle, Emily Browning, Bruce Langley, Yetide Badaki, Ian McShane, Omid Abtahi and Ashley Reyes. The series airs Sundays at 8:00 p.m. ET/PT on Starz.