Wartales

To finish the Arthes scenario you have to complete 4 different quests to get access to the final quest for the area. Those quests are as follows:

Choosing Sides: Go to Saint Eleor Abbey, which is west of Cortia. Speak to Abbot Theocene and take him Boethius Village, which is slightly southwest of the Saint Eleor Abbey. When you arrive at Boethius Village, Count Laheart’s guards will approach you. You must choose to attack them to proceed, don't worry about making him mad, they'll be friendly to you after the mission is over. Next go to the Unstable Bridge to the south. The Unstable Bridge can be crossed without accessing it as a location, but you must select it to resume the quest. The Abbot wants you to destroy the bridge pillars, but only someone with the Miner profession can do it. So select a Miner from your party and destroy the bridge. Once you've done this, exit and wait for a group of Count Laheart’s people to approach you on the map. Same as the last group, you have to fight them to progress. After you win, revisit the Unstable Bridge and speak to Abbot Theocene. You can escort him back to the Abbey, or fight him on the bridge. If you choose to fight, he’s a single combatant who can’t do much. It should be an easy win. Killing him completes the quest in Laheart's favor, while escorting him back counts as the quest being done in Vernalis's favor.

Sabotage: Go to the Spring Quarter, which is northwest of Cortia. Head past the Saint Eleor Abbey and when the path splits, follow the right path. Once the path goes straight, look to your left for a mine entrance to go inside. Speak to Odraeste who wants to poison one of Count Vernalis’s wells. You can choose to help or fight him to the death. Helping him is simple and counts as siding with Count Laheart, just accept to help him and throw a carcass into the water. Do note that after an in-game day you will be hunted down by a squad of Vernalis's men if you help sabotage. Fighting him is a bit more difficult as there's a lot more enemies than the 2 you see in the cave. Win the fight and leave the cave to side with Count Vernalis.

The Deserters: This quest can be started in three areas, which are Vernalis's Castle, Laheart's Castle, or the Legion Camp. The hardest path to complete this quest is the Legion route since you have to kill the deserters, while siding with Laheart or Vernalis only requires you to recruit the 2 of the 3 groups of deserters for 20 influence each. Either way, helping either Count is the much easier path.

The Black Caravans: By far the hardest quest of the region, even with a level 6 party of 14 men I was struggling here. You find this quest at Count Laheart’s Castle, which is southwest of Cortia. Head southwest of Cortia and follow the path. You will eventually see the castle on your right. Speak to Captain Hostes to begin. Captain Hostes will join your party and direct you to an area east of Vernalis's Castle. You have to ambush a Black Caravan, which is the caravans you'll see passing by with a pitchfork symbol above their heads. This battle is hard. The only tips I can really give is to kill the weaker enemies first and to keep the axemen engaged in single combat since their attack is devastating if they hit you first. After the battle, you have to follow a caravan to their source, which means finding another black caravan. Wait around the area for a black caravan to head to your right, and follow them. Don’t follow the caravans going to the left; they are going to Count Vernalis's Castle. After following them up the mountain path you'll find a Concealed Camp. Be prepared for a fight before you investigate the camp, SO FOR THE LOVE OF GOD SAVE HERE, THIS FIGHT MAKES THE LAST ONE LOOK LIKE A CAKE WALK. Rest your men and heal up if you have to, you'll need it. You will meet Inquisitor Octavia at the camp, and you cannot avoid fighting her. Her forces are all Level 6, and will put up a fight if you haven’t been training/acquiring better gear. Surrounding all enemies with a large number of units is one of the best ways to take them down. Use durable units to stall any attackers, then surround the enemies to pick them off. This fight is simply and plainly COMPLETE BULLSHIT. Keep an eye on the enemy zealots, their attacks are devastating since they hit you until they apply fever meaning that they can whack your men over and over again until you die, so kill these ones first. During this fight you must also protect Captain Hostes since if he dies the fight ends. After you slog through the fight and win you have to speak to Captain Hostes in the camp for your reward. When speaking to him you can either accept your reward and support Count Laheart, or kill Captain Hostes for the camps loot and support Count Vernalis. Either way ends the quest.

The Fate of Arthes: This is it, the final quest of this god forsaken area. Depending on your previous choices in the other quests you have to report to either Laheart or Vernalis. Both are functionally the same and have the same troops, so it doesn't really matter. Go to your Count you supported and speak to him. Now go to the opposing Count's castle and join in the battle. Thankfully this battle is nowhere near as difficult as the Black Caravan was, so you can easily wipe up the other Count. After finishing the fight speak to the Count you supported and claim your reward to finish The Fate of Arthes.