Imagine this. You are an imerial legion legit. You are then sent by General Tullius himself to the reach. Your mission is simple. To command all legion forces in wiping out the Forsworn permanently. So what tatics would you use?

The same that they use. Stealth and Guerrilla Warfare.

interesting..

Resignation
Without wiping out the whole of the population that supports and hides them defeating a guerilla army isn't possible, although suppressing them for a while might be
I didn't join the Legion to massacare civilians

Spy on their forts, see where they get their water from and poison the source. Have some of our men under guise as their one of their own to assassinate any healers that attempt to aid those who survive.

Just using massive numbers doesn't work when fighting that kind of an enemy. If America didn't use the tactical advantages during the American Revolution and just met face to face with the British then I would be drinking tea and praising the Queen of England right now.

That's why we don't fight with huge numbers anymore. We move in small squads, take any kind of tactical advantage you can get, and use communication and precision.

I do agree on this. In a situation like this if you think like the enemy you could defeat him.

And what next?

The most of them are rather primitive so that'll hopefully kill off quite a few of them. If possible I'd like to capture a briar heart and interrogate them. See if there's any suprise magic we don't know about. Forsworn also seem to revere hagravens, if there are any battlemages to spare I'd either lay an ambush for any known hagravens and capture it, make it look like a group of brigands got ahold of it and when forsworn chagre to save it greet them with a volley of arrows.
I'd also either try and imprison a hagraven at some forts and keep it under hidden watch. It could draw out forsworn spies. Another tactic would to try and pose one of our own as a forsworn prisoner, see if any spies try anything. If so, Shiv to the gut.

Not sure, but I would try to locate high-ranking Forsworn and have the killed, cutting the head of the snake as it were. The rest would likely disolve after a while, or tear each others apart in petty squables over who will be the next king of the Reach.

They're not civilians, they're not even civilized.
They're akin to terrorists.

I'd focus on assassinating Hagravens, as they're either leaders or religious icons. Eitherway they hold sway.
Then I'd work on crushing some of the encampments in the ancient redoubts.

Ok. Interesting.. And if that plan of yours worked. How are you going to kill them of? or did you already did that?

The forsworn bug me. They remind me of the various gangs from FONV. They have no fleshed out story and just seem fake and out of place. Why don't they have any "culture"?

Also for Bretons they sure seem big

sorry to be rude but this is not meant to complain about them. It's a what if you were responsible of killing them of.

I would just let the Nords out...

A bottle of mead for a Forsworn head!!!

Talk about total depopulation of the area lol.

Good idea!

Well between poisioning a major hideouts killing masses of them at once, torturing briar hearts for information and defiling something similar to their queens, the forsworn can only get demoralised or angry. If they get demoralised they'll dissipate and the remnants will be similar to dealing with bandits. They'd be a priority for the guard, and we could set up a bounty to reward people who hunt them down or provide beneficial information.
If they only get angrier they'll become more brash and hasty to cause action against us. This could mean they'll try full out assaults, wherein we'll be prepared considering we have a legion (and hopefully a few battlemages) they'll be sufficiently whiped out. Or they'll try to attack from within. Hence why I have the false prisoner plan to prevent espionage. If possible I'd like a seperate Barracks for my legion from the guards, makes it easier to keep track of my men and prevent infiltration.

So how do you distinguish terrorists from civilians or are you just going to assume any non-Nord in The Reach is a Forsworn terrorist or supporter

Now that would be quite affective

Focus all my troops in one place then find the Forsworn largest fortress, take that fortress then make it your own head quarter then from there send troops to crush the remaining Forsworn's settlements one by one!

consider the mistakes of my life and how i ended up being a slave to some imperial fool, if ulfric or someone from argonia sent me on the other hand...i would simply splice their chain of command* and always know their orders and relays before they even get to who they are supposed to get to, then i would bury them alive in their own caves (fire balls can fix any problem), poison any near a water source and hire mercenarys to slaughter any other encampments, although there may be some situational things but my actions would usually revolve around what i mentioned

*to get into the chain of command i would either tourture/bribe/threaten a runner/high ranking member/whatever untill he agreed to send everything through me first or i would earn the trust of the foresworn by feigning crimes against the nords and torument from the nords then earn my way too a trusted rank (maybe greasing some palms to make the process go faster)

What time frame am I working with?

If I have the time
I would try to turn group against group and let them do the heavy lifting.I would also see if there were any I could negotiate with and offer land for peace.

If not
Fire lots of fire

Well for a starter, the ones with a plant in their chest cavity.
Then anyone who's wearing a deer head. Then pretty much any other fanatical who's trying to kill me in that area.

The Forsworn aren't exactly inconspicuous.

I'd also like to add, if it's possible, that if I cannot poison forsworn's water supplies then I would simply destroy the forts they reside in with fire and oil. Burn the forts down if they have no use in modern society, bury them within their hole. capture any who escape, kill all who resist.

I don't really like to be ordered to mass murder a whole population, so I'd probably cut Tullius' head off on the spot.