Episode 7 of The Trigan Empire
War with Hericon
aka Truce with Hericon (Hamlyn reprint)
Oorlog met Hericon (Dutch title)
War with Hericon (Dutch title, translated)
Written by Mike Butterworth
Illustrated by Don Lawrence
War with Hericon was originally published in 9 instalments in issues 256 (10 December 1966) to 264 (4 February 1967) of Look and Learn magazine.
It was reprinted in 1975 in Vulcan comic.
It was reprinted in 1978 as Truce with Hericon in The Trigan Empire (Hamlyn/Chartwell).
It is reprinted in Volume 2 of The Trigan Empire—The Collection (the Don Lawrence Collection).
It is reprinted in Volume 1 of The Rise and Fall of the Trigan Empire (Rebellion).

Plot summary
The kingdom of Hericon is a powerful realm on the other side of the Great Ocean. Kassar rules over Hericon. Trigo signs a trade agreement with him and marries his sister Ursa.
The merchant Yenni abuses the agreement and is sentenced to be branded as a thief on the forehead. He goes to Trigo and demands revenge based on an ancient law of retribution. Trigo is forced to comply and brands a market vendor from Hericon. This incident escalates into a war between Trigan City and Hericon.
Yenni wants to kill Trigo’s wife because she is from Hericon. For this, he is banished. To avoid putting Trigo in danger, Ursa decides to flee to Hericon. But she is kidnapped by Yenni, who takes her to the desert people, the Nilds. They demand a ransom from Trigo and Kassar.
Kassar marches with a large army to Trigan City. But before they engage in battle, Trigo and Kassar go to rescue Ursa. Kassar is captured by the Nilds, but Trigo frees them by threatening to kill their sacred Yalt, a sabre-toothed beast. They are released by the Nilds and take Yenni, now captive, with them. Kassar and Trigo forget the foolish war and sign a peace treaty.

Links
https://www.catawiki.com/en/l/60634181-don-lawrence-originele-gouache-op-board-cover-trigie-deel-3-stad-onder-vuur-1993
Plot summary (Dutch)
Downloads
MediaFire via British Comics Compilations