From ErfWiki

Proposed Canon

Unaroyal is a side in the Royal Crown Coalition. Its infantry units are clad in red and orange livery.^Erf-b1-p128 Their banner seems to be a black torus with white lettering, on a red and orange field.

It sent 1714 troops into battle, led by the Warlord known as Scarlet. This was the third largest force after the Marbits and Jetstone. They were wiped out in the battle and the volcano eruption that followed.

Following the destruction of their forces, Unaroyal's Thinkamancer informed Transylvito's Thinkamancer, Bunny, of the loss.^Erf-b1-p138

Speculation

Seems to be on relatively good terms with Transylvito.

They have apperantly took Warchalking from Lord Manpower the Temporary at the begining of book one.

Real World References

"Unaroyal" is likely a pun on the tire manufacturer Uniroyal.