I believe that may thinking on many matters in Redwall is unorthodox after reading the reaction to my first blog post. In any case, I shall now make the argument that Verdauga Greeneyes, Lord of Kotir, is a gray character. Understand that I am not using the typical Redwall definition of gray. I do not mean a good vermin. I will ignore his species and in turn substitute gray as meaning morally ambiguous. To start there was the matter of driving Luke and his tribe out of St. Ninian's. You can say,"Evil warlord! He drove good woodlanders out of their home!" Yes, but also no. Luke's tribe might have just retreated rather than been forced out. He appears even kinder if he did force them out. Most warlords would have tortured, killed, and enslaved defeated enemies. Getting driven out is mild by comparison.
When Martin came along, Verdauga let him live. Yes, Gingivere might have convinced him to do so, but he could have listened to Tsarmina or just given the execution order himself. Verdauga also respected Martin's courage. He told Tsarmina that he had seen courage in all shapes and sizes, and he gave Martin one of the better cells. How many vermin leaders respect bravery? Ungatt Trunn seems like he might when he tells Groddil that the hares of Salamandastron are brave, but then he acts like a coward and seeks to kill Brocktree through trickery. Badrang pretends to, but all he wants to do is profit off of Martin's courage.
Now to Verdauga's evil actions. These are why I am arguing he is gray rather than good. He violently put down the first resistance and killed its leaders. Of course he was a warlord, but that explains rather than excuses his actions. He also must have done some terrible things as a warlord in the Northlands, but I can't say what they are as they are never revealed.