This is for Isro btw, Sro-R got little changes from it (differences are written near the end)

When you grind at +35 level mobs, you will start to see forgotten world pillars (Looks like a red diamond), when you destroy it, it will summon ~ 7 Envy mobs, they are champion mobs btw and would be harder to kill than surrounding mobs in most cases.

The dimension pillars only get summoned once every 400 mobs (estimated).

Anyway shouldn't be too hard to kill them if you are buffed or a bit careful, When the "Envies" get killed, they have a chance to drop Forgotten world Holes.

Just use a "hole" in a town and it will summon a teleporter that leads you to the Forgotten world map.

The level of the forgotten world is written on the forgotten world holes (the numbers of squares/stars on it).

Level 1 = Normal mobs.
Level 2 = Champion mobs.
level 3,4 (only high level dimension pillars can drop them from Envies) = Elite mobs.

1 star is fairly easy to do it alone, 2 star can be done alone with good gear/skill [Not ingame skills ], but it is easier to do it in a party.

3-4 are impossible to be done alone and needs a good party.

1,2 star you can summon up to 4 people in a single party, 3,4 star you can summon up to 8 people.

There are many mini-uniques in Fgw and 1 last powerful unique (After you defeat every other unique it gets summoned) that unique can summon the other mini-uniques you killed before.

You can enter a fgw only once every 5 hours.

1 last thing:
Every fgw got 2 treasure boxes in a fixed place, when you destroy those boxes, you get a chance for them to drop tailsmans, when you collect 8 different kinds of tailsmans you can trade them with an Npc for a Sun weapon of your choice.

Generally the last two tailsmans of the 8 are the rarest.

There are different maps of fgw, each with there own set of tailsmans and their own prizes to collect the 8.

Example:

Togui village fgw = 8D sun weapon of choice for collecting the 8 tailsmans for it.

Flame mountain fgw = 9D sun weapon of choice.

90-100 Shipwreck = 10D Seal of moon weapon of choice.

101-110 Shipwreck (different map) = 11D Seal of Nova weapon (A grade) of choice for collecting the 8 tailsmans for it.

A few changes in Sro-R from Isro :

but in SRO-R maximum 2 envies get summoned.
and you get the faded beads from the mini uniques and they give u random SP ((From 200 sp Up to 20k sp))
and in SRO-R you can re-enter FGW every 3 hours.

There are 3 bars

Yellow bar:
8 hours
100% exp/sp gain when killing mobs
100% chance to get items (i mean that the chance doesn't decrease)

Red bar:
4 hours
50% exp/sp gain
half the chance to get a drop (quest or regular drops)

Grey bar:
12 hours (or the rest of the day)
0% chance to get items
0 exp/sp gain

In other words, after 12 hours of logging in you get no items/exp and have to wait till the next "joymax" day.