MOST HOSTILE CHARACTER

[martins#1fan]

...Gulo....a cannibalistic wolverine that charges just about everything that he doestn' like or just literally will have u for dinner if he doesnt' like u, you  can't get any more hostile than that!

Well said, CURSE YOU
                                                            GULO!!!

[Taggerung_of_Redwall]

Gulo was a very good villain. Obviously not a good creature, but a good character.

And adders haven't been brought up yet. I'd give them a good deal of credit on their hostility.
Going with the definitons of hostile as best befits this topic: characterized by enmity or ill will; "a hostile nation"; "a hostile remark"; "hostile actions", Unfriendly; antagonistic or opposed to something or someone

Adders live and thrive on evil, hate everybeast, very much so exclusively antagonists, and on the subject of oppostion, they were for one totally independent and self-living, never being apart of a horde or subject to anybeast (with the exception of other adder(s)). The adders we see exist almost always by themselves, causing massive havoc and chaos, generally consuming and taking out villains and heroes alike, not at all interested in the struggles going on between them, or giving a thought to the errands that heroes might be on, ambushing them regardless (Mariel of Redwall).
And then there's Mister Death. xDD. I loved Brookflow and Sister Armel, giving them a stuck-up little adder that Brooky couldn't make up her mind about whether it was an adder or grass snake and laughing and joking the whole while was brillaint.

[Log-a-Log]

Cregga with her huge axepike and the Bloodwrath is the most hostile character

[Folgrimeo]

After the events in "The Rogue Crew", I'm inclined to think of Razzid Wearat as one of the most hostile characters, for seeing his own troops as expendable and dealing a lot of pain. I'd also nominate Slipp from "The Bellmaker" for the derision he had for his good-hearted comrade Blaggut, especially in a climatic moment where he takes out his anger on Blaggut.

The most hostile character in my opinion is Tugga Bruster the shrew, from "Doomwyte". A goodbeast with bad manners, he insulted the Abbey food, he was remarkably cold towards vermin, and never missed an opportunity to criticize teammates. He was an interesting anomaly for being someone that nobody in the book liked.

[martins#1fan]

I didn't like The Rouge Crew that much.

[Skalrag of Marshank]

Slipp from The Bellmaker was kinda cranky. I never really liked Druwp from Martin the Warrior, either.

[Log-a-Log]

Druwp! I have always hated him

[Skalrag of Marshank]

He's such a jerk! I like Skalrag, though. (Duh! ) I've always thought it weird that Skalrag is my favorite character and Druwp is my least favorite chracter.

[Blademaster]

Axtel Sturnclaw for the win BLOODWRATH moles are fun. 

[Nightfire]

Umm, Druwp may have been annoying and a traitor, but he wasn't hostile in the least bit.

And I think Cregga was very hostile.

Sawney Rath as well; I mean, he would maim his own clanbeasts for no good reason at all! Although ruining Felch's paw was for a good reason: to protect Deyna.

[Plugg Firetail]

Nightfire I think you mean Sawney Rath.

[Lord Brock]

I could name a hostile villain, but i'd say for the "good" characters Tugga Bruster from Doomwyte was quite hostile.

[Folgrimeo]

Interesting that some people have nominated Cregga. At first I thought maybe it's because of their behavior when they're under the Bloodwrath, but then I recalled all the male badgers at Salamandastron with their one-track minds. They don't seem content to just live life peacefully, they always have to prepare for a future invasion and talk about war strategies. So they could be hostile because of the stress of there always being lives at stake. Can't recall which badger I'd nominate since I don't remember what they're like when talking to other goodbeasts (except Mandoral who's so gentle when he talked to Tiria)... so I guess I'd nominate Boar from "Mossflower". Maybe because I just don't see kindness when he puts that full-body armor and helmet on.

[Nightfire]

Nightfire I think you mean Sawney Rath.

Oops!  Sorry, I did mean to write Sawney Rath. It just came out different, I guess. I changed it.

[Superdreuzel]

I think I'll vote for either Slagar the Cruel or Tsarmina

Stealing babies is pretty hardcore, but so is throwing Martin in a cell and break his sword.
Hmm... Decissions...