Tergen was a fierce male goshawk who lived in Mossflower Woods. He was very proud and quick-tempered, but fiercely loyal; he also had an obsesson with killing vermin.
He was shot in the wing by Gulo the Savage's horde; the arrow wound crippled him and prevented him from flying. He mistook Rakkety Tam MacBurl for a vermin and attacked him; once he realized his error, he slew an ermine that had been following them both. He then joined up with the Long Patrol and was ordered to travel to Redwall Abbey with Ferdimond de Mayne and Yoofus Lightpaw to warn the Abbey dwellers about Gulo.At Redwall Abbey, Tergen refused to allow his wing to be treated at first, fearing that Sister Armel would want to amputate it; however Armel put his wing in a splint, telling him not to try to fly with it. As Tergen felt useless while unable to fly, Brigadier Buckworthy Crumshaw took pity and assigned him to wall duty, reasoning that the sharp eyes of a hawk might come in handy. Because of this, Tergen became firm friends with Crumshaw, affectionately referring to the hare as "Brigadier Wotwot."
Tergen was the first to spot the approaching vermin on two occasions, which gave the Long Patrol ample time to prepare for them and set traps. When Crumshaw was slain in battle, Tergen grieved for him, giving up wall duty to sulk inside the Abbey Building.
Later, he was one of the marshals of the duel between Gulo and Rakkety Tam. He then traveled with Tam and his family to Salamandastron, where he stayed on as a sentry.
- Krar Woodwatcher and Tergen are the only goshawks in the Redwall series.