The MWGS is a craftable legendary item with +30 to the Battle Stat. The items used in crafting it come exclusively from the Blacksmith, so if you plan to craft a MWGS, begin crafting the components for it as soon as you build the Blacksmith--you'll save yourself a lot of time later on!
Specifically, you will need to produce:
12 x Shortswords
6 x Broadswords
3 x Hefty Broadswords
1 x Masterwork Greatsword
To do this, you will also need the following uncommon resources:
38 x Steel
22 x Hard Wood
The best adventures to gather these resources are:
|Hard Wood||III||13||Fight in the Tourney|
|Steel||III||17||Save Wounded Soldiers|
The total crafting time required to make the MWGS, without counting upgrade/speedups, is 155 hours: 38H for the MWGS itself, 15H x 3 for the Hefty Broadswords, 6 x 6H for the Broadswords, and 12 x 3H for the Shortsword. That's nearly a full week of crafting.
Martells get a bonus to weapon production speed, and Baratheons a bonus to superior result chance; so if you plan to produce a lot of MWGS, either of these Fealties would be a good choice.
If you see any of the above listed items in the shop, buy them to save yourself some time crafting!
And when your MWGS is in production, add a red gem to give it a 50% increased chance of a superior result. Even if you plan to put it towards an eCav, getting a decent prefix/suffix for a MWGS would make it a worthwhile perm. Just imagine a MWGS of the Stag, 35 Battle and 10% to Fight for attack/defense! There's only a small chance of crafting it with that roll, but the chance is well worth a red gem.