there are several key milestone in the game:
1) World Map 10-10 to unlock Moon Light summon
2) Abyss 3x, 5x, 7x perfect stat equip set
3) Wyvern 11 for best Speed, Crit, Hit sets

completing World 10-10 will enable usage of gold transmit & ML bookmark to summon ML
completing Abyss 3x, 5x, 7x gives u the equip needed to move to better challenges
Hunt gives equip

in detail, difficulty as follows:
World 10-10 -> Abyss -> Hunt -> Labyrinth -> Raid -> Arena -> Guild War

if you are in Global, feel free to join LYN guild, we offer:
>> 24hour daily guild buff
>> Guild Wars guidance
>> Challenger rank Arena guidance
>> 18 Malaysians +8GMT LINE round-the-clock discussion

LINE chat group https://line.me/R/ti/g/c1RBopuHbR