Operation Righteous Smackdown
The only joint-Arda/Triumvirate of Yut military operation. The nation of Sigma Octavus, newly founded, declared war on "the entire world." The nations of Scolopendra, Karmabaijan, and Melkor Unchained took this threat seriously and responded as appropriate, jointly invading Sigma Octavus and completely destroying its military.
After the invasion, Sigma Octavus was then impelled to install a more stable government and became a productive member of the international community, over time. Operation Righteous Smackdown marks the high point of Triumvirate/Arda relations, quickly degrading back to open hostility soon afterwards.