A few days ago
@Leo-rah and I had a discussion about Vervain as he appeared in the old cartoon series.
It started with "Damn this character is just created to be disliked!"
And then... we talked about him and his intentions, why he might be that insanely loyal to Woundwort and we created a whole (headcanon) background-story about him

We will share it soon in another post. If a character, no matter how annoying and "evil" he might be, gets a decent backgroundstory.... people have it a lot easier to empathize with it.
Also I am rewatching the 1999 series again rn (after like... 15 years? I just finished Season 3 Episode 8 "Darkhaven") and I noticed a few things about Vervain.
He appeared VERY loyal to Woundwort in the beginning and was always trying to please.
He left Woundwort when Efrafa was destroyed and he was sure about the generals death.
He felt pity and tried to convince Woundwort to help the Redstone rabbits when their warren was invaded by humans.
It is obvious that he is very uncomfortable to be around Woundwort - yet he has no other place to go.
So after all I am very sure there is more behind Vervains fassade... if you just dig a little deeper