Tetra is one of the players trapped in the MMORPG Elder Tale. She is actually male in real life, but used a female Human Cleric-Idol character at the time of the Catastrophe and was thus stuck in it, though she seems to have adjusted to her new body and has not displayed any desire to change back to a male body. She is a self-proclaimed "Galaxy Idol," and has Equipment to fit the part, but is rather bad at singing herself. She was a part of the Abyssal Shaft Raid Party as a member of Light Indigo, but then joined Log Horizon near the end of the raid. She later joins the Shibuya Raid Team.

(Source: Log Horizon wikia)