IntroductionTo get this achievement you have to get approximately 260.000 gold per character and buy all the upgrades from all the 4 main characters. The last upgrade unlocks at level 49. Nothing carries over from character to character so it's all done in parallel
Summary:1) With a new character get to level 50 (read my guide on how to do that easily)
2) Get the Health Totem, Health Potion and optionally Energy Totem items and their upgrades
3) Get Deity difficulty unlocked by playing the last level and beating Zane on any difficulty
4) Repeat the mission
Bravelake Flat or
Gloom ValeMore detailed:1) When you start out with a character you will have to beat the first level. There is no new game+ system so nothing transfers over. Luckily through an exploit you can become instant level 50. More on that you can read in my guide:
Solution for Veteran In Sacred 3If you don't have a friend for the level up process you can choose to do the grindy part yourself. If you're going for the grind, start at level 40, you'll still get XP while gold grinding
2) Play the missions:
HaliosSkaldera
Agari Glen
Hermit's Path
OakshadeSunken Ramparts
Valam Lake
Bravelake Flat
And optionally:
Lost CatacombsFendrel Woods
Urkus Swamp
Goldpeak Mine
3)Now you're going to unlock Deity difficulty. You can either join someone playing the last mission Azgarth or you're going to unlock it yourself by playing all Main Missions (preferbly on champion difficulty)
4) With those items and their upgrades you should have some gold in your pockets. Except for the missions in bold it is wise to repeat the mentioned missions on Deity difficulty so you upgrade them further.
Either way now the grinding begins and you should keep repeating Bravelake Flat and / or Gloom Vale on Deity difficulty to keep getting around 2000 gold. This number is not fixed and you can sometimes get 3000 or merely 1600. Either way you will have to keep repeating those missions until you have enough gold. Make sure to use the 3rd upgrade for the Block so you repel x2 the damage done to you. Don't refill your potions etc, the auto-refill upgrades should keep you well enough stocked every time.
This process should take about 3,5-4,5h per character. If you still have to play through Deity difficulty on the campaign, do that first, that saves doing an entire character.
Good luck!