From Diablo Wiki
You can find which Merchants you have met by looking at your Achievements in game, under General > Exploration and scroll down to 'Market Research' and expand that menu.
| Market Research
|10|| Meet the following wandering merchants.
 Wandering Tinker
- From the Quest Selection screen take quest No. 6. The Broken Blade.
- Accept the quest from Leah in Tristram.
- Take the Waypoint from Tristram to the Fields of Misery.
- Whichever waypoint you appear at you need to head north until you hit the north edge of the map.
- Follow the edge along and at some point you will come to some mud steps which will lead up to a Sheltered Cottage.
- Outside could be Swickard's Corpse which will loot the Farmer's Journal or a bag (Tinker's Possessions) containing the Wandering Tinker's Diary.
- If the cottage is the Tinker's Hovel, the Wandering Tinker will be inside.
- If what you are looking for is not there carry on along the top of the map until you reach the slope up to The Old Mill where you will get a Checkpoint. Leave the game and Resume Game and take the portal waiting for you in Tristram directly back to the slope.
- Run along the top of the map again looking for the steps.
 Rodger the Alchemist
- From the Quest Selection screen take Act I quest No. 8. Trailing the Coven.
- Take the quest from Leah.
- Take the waypoint from Tristram to Wortham Chapel.
- Leave Wortham out the town gate to the north.
- Across the bridge and to the other side where Rodger the Alchemist could be waiting for you.
- If he is not there head to the left and down the stairs to the Crazed Hermit where you get a Checkpoint.
- Leave the game, Resume Game and take the Town Portal waiting for you in Tristram directly back to the Crazed Hermit and make your way back up the stairs to the end of the bridge.
- If Rodger the Alchemist appears it will be at the end of the bridge, nowhere else.
 Vendel the Armorsmith
- Take quest No. 8 Trailing the Coven > Khazra Barricade and take the waypoint to Highlands Crossing.
- Make your way directly across the Southern Highlands.
- If the Watch Tower has spawned it's almost directly opposite this entrance into the Southern Highlands so try to keep going dead straight. See it on the Southern Highlands map marked (A).
- Head to the very west of the Southern Highlands.
- If you see Karyna's Lost Wagon approach it as you'll get a Checkpoint as you do so which means if you need to leave and 'Resume Game' you'll resume here and it'll save a little time.
- Although the Watch Tower may spawn it does not mean that Vendel the Armorsmith and his Scabbard event will.
 Adenah the Curio Vendor
- There are three places the house can spawn as indicated by the No. 3's on the Fields of Misery map.
- The house, Adenah and her jottings all feature in achievements.
 Kyr the Weaponsmith
- Take quest No. 9 The Imprisoned Angel > The Cursed Hold.
- Take the Waypoint to level 2 of the Halls of Agony and find the exit up to the Highlands Passage. See the Highlands Passage map.
- As you pass to the Highlands Passage you'll get a checkpoint. This is where Kyr the Weaponsmith will appear.
- If he is not there simply leave and resume and you will appear in the same place. Repeat until Kyr appears.
 Zaven the Alchemist
- From the Quest Selection screen take Act II quest No. 6. Betrayer of the Horadrim.
- Take the Waypoint in the Hidden Camp to the Path to the Oasis. You'll get a Checkpoint as soon as you materialise.
- Go down the Path to the Oasis and into the Dahlgur Oasis
- Go right hugging the edge of the map and take the first right. This is a small cul-de-sac with a waterfall and could be where Zaven appears. If not go straight back out and head north.
- Hug the right edge of the map and eventually you will come to another identical cul-de-sac. This is the second location Zaven could be. He could be in neither.
- If he is not, leave the game and Resume Game to appear back at the Path to the Oasis.
- You might consider only looking for the first spot he can appear in as that is so close to the Waypoint in the Path to the Oasis so it is very quick to see he isn't there and restart. You can see by the Dahlgur Oasis map that the spot further north is quite a trek and you'll be pestered by beasties on the way up too.
- When you've found and saved Zaven the Mysterious Cave will open behind him and this is where you may find the Liquid Rainbow, one of the ingredients needed for the Staff of Herding. It will appear in a Mysterious Chest which has a possibility of spawning (doesn't always).
- From the Quest Selection screen take Act II quest No. 2. The Road to Alcarnus.
- Take the Waypoint in the Hidden Camp to the Black Canyon Mines.
- Once you have materialised take a couple of steps to the right. If you see the Blood Cellar door open leave the game and resume as the Deserted Cellar won't appear.
- If the Blood Cellar is not there head left and hug the bottom of the map.
- Within a very short distance is the first possible location of the Deserted Cellar.
- If not there head directly north. At the very north, right hand side of the gate into the Stinging Winds is the other possible spawn location.
- If the Deserted Cellar doesn't appear in either place or it doesn't contain what you're looking for, leave and Resume Game to appear back at the waypoint in the Hidden Camp.
 Halmin the Alchemist
- From the Quest Selection screen take Act III > quest No. 5. Machines of War.
- Head out of Bastion's Keep through the Arreat Gate.
- Head left (your character's left) down the steps and then left down more steps.
- As you leave the gate and into The Battlefields head to your right below the burning cart.
- The Foundry is nearby, relatively central.
- Leave and Resume Game if it's not there, no need to explore the rest of The Battlefields.
- If Halmin the Alchemist appears it will always be on level 1 in a room with a fireplace in it. Once the mobs in the room are killed, Halmin will get out from under the bed, presumably he was hiding from the monsters there.
|Achievements General Campaign Cooperative Hardcore Classes Challenges Crafting Feats of Strength|
• Level 10 *
• Demon Hunter
• Stop Hitting Yourself
• Made to Order *
• Return Business *