Could carrying multiple weapons at the hip be at all practical? My rogue knight, he’s paranoid so he carries a dagger, a tomahawk, a broadsword, and a scimitar on him at almost all times. Would this work in any way?
There’s a few questions here.
Multiple weapons is normal. That’s not even a paranoia thing. At the very least, a character would carry a primary weapon (maybe a spear or other polearm), and a sidearm (a sword, battle axe, or something similar.) They’d probably also carry a dagger. Historically these were a combination of eating implement, multipurpose tool, and emergency weapon. Depending on context, they may also carry a shield (which is, ultimately a weapon in its own right.)
A hatchet would end up in a kind odd state here. It’s reasonable for them to carry it as a tool. They probably wouldn’t use it in combat by choice, but if it’s the only thing you can reach, sure. This puts it in a similar class to the dagger, but carrying both would still make sense.
It’s also possible, depending on their culture, that they’d carry throwing weapons. Throwing axes or javelins are the two that come to mind. (Probably because you mentioned tomahawks.)
The term tomahawk throws me off a bit. The word is Algonquian. This isn’t a bad thing, but it is something to keep in mind if your setting is a pseudo-medieval Europe. Trade off is, if you’re wanting a “New World Colonization,” theme, then yeah, a tomahawk would make sense. Though, at that point, your character would probably be carrying a musket as their primary, a pistol (or several), a saber, possibly a bow, a knife, and said tomahawk. Again, nothing wrong with this if you want to step into an early modern setting (think 17th century), it is an incredibly interesting era that’s undeserved in popular fantasy. So, feel free. Though, you might want to do some additional research before you jump in.
There’s another weapon nitpick: the broadsword and scimitar combo is weird. The scimitar is Middle Eastern. The broadsword is an anachronism. Unless you have a character who’s dual wielding, I’d recommend only bringing one dedicated sidearm. (The pistols example above is an anomaly. Some combatants carried multiple black powder pistols and would simply swap out weapons instead of reloading them in combat. This was a rarity, and fell out of practice as faster reload systems became prevalent.)
So, we have an anachronism stew here. We’ve got a European knight, who’s using a Persian weapon, and a Native American weapon. This is a little odd. (The word, Scimitar, entered English from either French or Italian.) You can bring all of this together, but it’s worth remembering that weapons, (and martial arts) aren’t universal. Historically, these had regional roots. Picking them indiscriminately can, at best, result in an anachronistic mess, and at worst can be downright offensive.
I’m not sure what you’re after with, “rogue knight.” I mean, is he supposed to be multi-classed, because the real world didn’t work like that. A knight spent most of his life training for combat. There wasn’t really time for him to go out and develop a side career as a thief.
Now, if your setting has militant orders who train for clandestine warfare, sneaking in and around, that’s an option. There’s no real world equivalent. Modern special forces were an evolution of the extreme lethality of 19th and 20th century combat, though it’s possible a fantasy setting may have militant orders that operate like this.
Another possibility is that your character wanders around, basically of their own accord. In that case, the term you’re looking for is Knight Errant.
A former knight who’d been excommunicated could also be described as rogue. I’m not at all sure how that works out, but I’m confidant your character would have cause to be a bit paranoid if that were the case. Particularly if there are religious inquisitions on the lose. Most of the time we think of the Spanish Inquisition (15th century), but the inquisitions date back to the 12th. Militant orders date to the 10th, so there’s some overlap here.
Putting this together, it is possible, you have an excommunicated knight who fled to The New World to avoid inquisitorial scrutiny. This could get close to the specific combination of weapons you’re looking at, but we’re realistically talking mid 17th century here. Of course, with a fantasy setting, things start to shuffle around a bit.
So, in answer to your final question, could this work? Yes, but that loadout is a little awkward. You may want to do some further research on the era you’re looking at, before you start tweaking the world.