Being willing to start the fight with a corpse, or by crippling someone for life will do wonders for the situation. Adding a weapon that your character is willing and able to use moves this one into manageable territory. This gets into a range of psychological warfare, which we’ve actually discussed before.
Basically, this is a kind of threat management. All you need to do is make sure your opponents are unwilling or unable to fight. If your character is willing to kill someone, then unable is an easy threshold to hit; after all, it’s pretty hard to beat someone if you’re already dead.
Unwilling is a little harder to hit. If someone walks out of nowhere and summarily executes your buddy, odds are, you’re not going to want to mess with them and risk dying. If they just cripple your buddy, and look like they can keep doing that, again, that’s not something you’ll want a piece of. But, if someone simply attacks one of your friends, and you outnumber them four to one, you’ll probably feel a lot better about wading in.
This is all about creating a show of aggression that gets them to back off, but, the key is it’s an illusion, show any vulnerability and they’re willingness to fight will come back stronger. If you’re the one that’s outnumbered, this is very bad news.
Taking a hostage is also a viable way to make opponents unwilling to attack, but this one gets really complected quickly. First, the hostage’s buddies have to actually care about the hostage, which isn’t a certainty. Second, they need to believe that your character can and will harm the hostage. If the hostage is on their way to becoming corpse #2, then that’s covered, but if your character starts with taking a hostage, this could be up in the air. Finally, your character needs to have a clearly articulated objective. This is a short term solution, and if your character can’t use the hostage to leverage his buddies into doing what your character wants, it’s just a game of waiting for one of his buddies to do something stupid… well, stupider, and eventually they will.
Also, I know you stuck hero in quotes there, but this kind of a situation, and approach, will really subvert any attempt to make your character look heroic. If your character is willing to be a monster, then it is manageable.
Anyway, there’s more:
For the sake of context on my last ask, the time period is something like the late 1800s in a city the character isn’t tied to. With them is a person they care very much about who’s just been knocked out by these thugs, they (the character) intend to protect this person but he’s basically out of the picture for the duration of the fight. The character is scared, angry and won’t shy away from brutality. Is this a fight they can realistically win?
As a general rule, I’m not a fan of scrap wood over, say, an unattended piece of pipe. But, unless your character specifically brought a weapon with them, they’re limited to whatever they can get their hands on.
Depending on who these thugs are, and what your character is after, it might be winnable. An unconscious character is, ironically much easier to account for than someone who’s upright and an unknown quantity.
Not being a local, and (presumably) not hanging around in the same circles as the thugs will do wonders for keeping them out of any resulting criminal investigation (unless your character is distinctive in some way).
Now, scared and angry is a problem. Handling a situation like this requires a very cold, methodical approach. Being afraid and angry will work against that. An enraged foe is something the thugs should be afraid of, but if they sense that your character is afraid, the entire situation will go pear shaped. With anger, a genuinely enraged fighter is more likely to make mistakes and over commit. Anger also leads to tunnel vision, the combatant ignores, or sometimes outright loses their peripheral vision. In a real fight, particularly against multiple opponents, both of these will get people killed.
If they can escalate the brutality beyond anything the thugs can deal with, before a fight starts, then yes, they can get through it. If they can’t escalate quickly enough, then they’ll get swarmed.