Once you step into Lanfar, many of the quests won't last long outside dungeons, and dungeons in Lanfar are harsh. Let me say in comparison, Landel islands dungeons are a walk in tha park, pun intended. Therefore, you'll probably want Cerrydwen before you try to progress further. She's not only the best fighter you'll find for a long time, but also she's a T3 level Archelogist, Explorer and a T1,5 level carpenter as an added bonus; all for 2 defiance. Which means you can even team her with late game T4 fighters which occupy 20+ authority each.
Therefore I just finished this quest but it took too long because I couldn't find any decent English guide so I'm going to write one.
First off, this guide's purpose isn't leading you to quest locations, rather, to prepare you to the final fight. I'll still quickly note the quest steps but use http://www.shinhan.name/tsmap/
- Explore The Moccasin Inn. Get the quest. Don't worry about the warning.
- Explore Abandoned coastal village. Go to "find the tracks" locations on the Shinhan's map.
Now on the next step you will face 6 spiders with ~35 piercing damage and low blunt defense. These are also the same enemies you will face a lot in the dungeon (Dowen cellar). Don't try to kill these yet.
Now you need to prepare. First step is building a shelter or an inn with 32+ prestige to recruit 2x squires. This is a must because they are the only good blunt offenders and they have decent defense too. Three would be better but your authority points won't probably allow this anyways. If one of your squires has low stats, don't worry, you will bench one after you get Cerrydwen. The shelter/inn location doesn't matter (but if you want my advice, go for a 40 prestige/comfort Inn in the right location for your main trade - you'll eventually need it). In order to learn more about inns ans shelters, check this post: http://forum.theriansaga.com/viewtopic.php?f=37&t=127&p=988
You will also want to use Yraen only for the final boss of the dungeon. The last member of your team might be one of these: a Behiran (pet), a Vargr (pet) or Wojtek (quest pet). Wojtek's piercing def is terrible but he has decent blunt offense so you may use him if you can't have the rest, somehow (ie. you can't raise your taming to 27+). Sadly neither of Yraen, Behiran or Vargr have good blunt offense, so these will not help you except for the final boss both in terms of damage and tanking. I used a Behiran myself because I wanted to train one anyways.
Note: Normally you don't need an additional companion slot, but if you have one, no harm to bring along an additional good companion, keep reading.
Now, when you have time you may try to kill the spiders. Always tank with your hero to train his def stats. You should have at least ~22 defenses so that you can wear a decent level armor. When you manage to kill the spiders, it's time for armor. Either Exceptional Steel armor and Bronze plate will do the trick. You can't wear higher armor at this point anyways.
Also make or buy a 35+ blunt offense weapon. This is also important if you want your hero to hit the spiders for 70+ damage. Basicly if your off is higher than opponent's def, you take more than half of their health, which in turn means your hero + 2x squires will kill a spider in 1 round, unless it dodges a blow.
Finally make or buy 10-15 healing vials. Buying these might turn out expensive but it's worth it.
After you've done all of these you may want to try dowen cellar to train but don't waste any potions or vials for now. You can try to get into the room near the enterance and get the book. The book isn't needed but it's a good bonus quest item.
Important: to be able to finish the quest you need 22 cave skill (25 for book) so you either need a Varanus (if you have additional companion slot) or a 4+ cave jewel. It's cheap.
When you think you're ready, I urge you to buy a +3 def/off Coordination vial. Also if you're in a guild, ask someone to lend you their Scorpidus Ring (+3 to all off) and Arachnidas Brooch (+3 to all def). You might think these are not vital but +6 to all stats can make or break this quest. (Note that the said jewels are terribly expensive stuff so be sure to take care of them). Vial is not that expensive anyways (around 6g at the moment).
Now, make sure you have several hours, cause you want to get the best out of your vial. When you're ready, go to the dungeon door, drink your vial and drink a chimeric elixir (most probably you have one). This is in order to be able to drink the healing vials inside. Don't drink 2 cause you will delete the effects of the vial.
Now, tips for the dungeon:
- When inside always fight with your best team. One exception here may be using an additional companion (if you have one) right next to your hero, cause he may get hit. Still if that additional companion isn't a good one, it may hinder your path to the end boss.
- Always tank with your hero, cause he's the only one you can heal inside a dungeon (via healing vials). If your companions are damaged when you reach the boss, you will probably lose.
- Small spiders hit harder. Kill them 1 by 1 with your hero + 2 squires. Leave the large spiders to the end, they don't really matter. Small spiders hit for 15-80 damage and large spiders hit for a puny 7-12 damage.
- After each battle, heal your hero with vials if you need. Your health doesn't always have to be 100% full except the boss battle. You will battle 3-8 times till the end boss. More fights only mean you spend more healing vials.
- End boss, namely Shaman Spider has a 60+ piercing attack, 35 blunt def, 50 piercing def, 30 slashing def. He has 2 small and 2 large spider companions. As I said before large spiders are unimportant. In the first round, tank with your last companion (Behiran in my case). It will probably die but it will surely take the big hit from the boss so it will have served its purpose. In the first round, attack the boss with Yraen and kill a small spider with 2xsquires and your hero. If you can do this, the enemy will probably lose the 1 turn KO power. In the second round kill the other small spider while tanking with your hero. Now, the enemy has only the boss dealing serious damage (~70-80 each hit).
- Now attack the boss with Yraen, 1 squire and your hero. Tank with one of your squires for 1 round. Next round tank with your other squire. After both squires are damaged, attack with both squires and your hero and tank with Yraen. After this, let the boss damage your hero's 2 organs. Now, there's a serious risk of death so start sacrificing whatever companion you have left possibly leaving 1 squire alive if you can.
- I downed the boss with 1 squire alive and my hero. The large spiders left are squishy but don't let them somehow deal the finishing blow, so if your hero is seriously damaged, keep tanking with your squire.
- I died twice to this boss and you probably will, too. Just sleep for 45 mins or drink a phoenix and reenter until your Coord vial wears off. Don't be demoralized because you will be twice the better each time.
- And remember luck plays a big part.
Updated according to Valerian's advice.