The Mutai, also known as the "trial of blood," is an alien martial art and fighting tradition created by the Yolu as a means for settling disputes without resorting to war.
The principal rule of the Mutai was that the last man standing after a no-holds barred fight wins; this principle was taken so seriously that a contender could maim or even kill his opponent without punishment, providing that there was no cheating taking place.
Although it's practised by many other species for whom it is a greatly cherished tradition, an alien species has to earn the right to hold tournaments and have members train as Mutari. Back before the Yolu made contact with other races, or even united under one government, a Yolu nation or faction had to earn the right to compete, and after the Yolu made contact with aliens this rule was applied to them as well.
This right is earned through a member of said species either emerging victorious during a match against a local Sho-rin, or fighting him to a draw. Usual this is after being sponsored by a Muta-Do or Ka-Tow, although anyone can simply just issue a challenge as a Sho-rin is honour bound to accept all challenges (although circumventing the resident Muta-Do like that is often seen as disrespectful and it is almost always a last resort).
A Mutai is overseen by a Muta-Do, the "sayer," an elite veteran fighter who trains fighters, selects combatants and presides over all matches. During matches two competitors—referred to as "Mutari"—are expected to continue to fight until one or the other can no longer fight or until the Mutai-Do declares the match a draw. There are no rounds or protective gear allowed other than a simple gi-like garment.
The Mutai was created by the Yolu early in their history, perhaps as far back as 5,000 years before the Third Age of mankind. Originally developed as a way for rival nations and factions to settle disputes without resorting to war, it eventually developed into a synthesis of martial art, philosophy and sporting tournament.
A popular fixture of Yolu culture, as their civilisation developed space travel, they took it with them and it has since been adopted by many of the species that they made contact with.
In 2258 Walker Smith became the first Human allowed to compete. Though the Muta-Do initially rejected his clumsy, disrespectful attempt to join, he later challenged Gyor, the Babylon 5 Sho-rin. The fight ended in a draw and the Mutai-Do was impressed with Smith's performance and said that from that from that point on, humans may enter the ring as brothers to all Mutari.
Mutari wear different colour sashes to denote rank and competence over a gi-like garment that also features the similarly symbol of the individual Mutari's world or race on the left breast. Lower ranking Mutari wear a yellow sash, higher ranking Mutari wear red and Mutai-Do wear a long robe with a purple coloured symbol. The Ka-Tow wear a training vest with a two pronged circular symbol on the left breast.
- Ka-Tow: A coach or "second" to a Mutari. A Mutari may have more than one Ka-Tow and they are sometimes former Mutari themselves.
- Mutari: The collective name for those that fight in the Mutari, who walk in the Sands of Blood.
- Muta-Do: Leader of a local Mutai championship and match referee.
- Sho-rin: Champion of a local Mutai. Referred to as the master of the Mutai, bravest of the brave.
- It's unclear how many species have actually earned the right to compete in the Mutai. Centauri, Hurr, Llort, Iksha, Hyach, Markab, pak'ma'ra and Narn have been seen in the audience during tournaments, but it's unclear if they can field fighters of their own.
- Of all the species in the Babylon 5 universe, only the Minbari have been expressly stated as not being allowed to take part in the Mutai (other than Humans who later earn the right). This is due to no member of their species ever winning and/or taking part in any tournament (''It ain't their thing'') .