So I have tried this map like 6 times, out of which 3 times I failed right before entering the Horn of Magnus Tower, more or less because of the seemingly everpresent (it was there all 3 times out of 3) patrol which circulates around the rooftops. Which would be fine, except it seems to be unavoidable, at least the legend version of it anyway, since it is so long, so there is no way I could hide in the house on the rooftop they pass by, and run when they go farther, since they turn around almost immediately and I believe there is no way to avoid pulling either the front or the tail of the patrol in this instance.
while i dont see how a single patrol you can see a mile away is a problem
here are my 2 cents on the matter :
group up wait for the patrol to get near the bridge throw an explosive bomb in the middle of the patrol over the shieldvermin , deal with whats left over continue
you dont have a bomb : maybe there is an Ironbreaker in your party
same story, wait for them to be close to the bridge, IB taunts them the party kills them all
you dont have a bomb or an ironbreaker
then just use what ever other class you have there and spam your ultis and destroy them
but it is highly unlikly that at this point of the map noboy in your group as not picked up any bomb
so just bomb them
same thing applys to chaos patrol
the horn fight is really not a big deal (sadly)
so you wont need potions or bombs there so if that patrol is that much of a roadblock just use pots and bombs on it and happly finsih the map
I often play with bots, who deal with chaos patrols on legend very unreliably, and while they do give you bombs once you´ve used yours, they often don´t do it immediately if engaged.
run in house. that patrol is same as vt1. (close by bridge there is a wooden door<— that room)
or open all chests to trigger vt1 grim room and hide there.
i can think of 2 more room where u can hide but u will figure it out at some point.