There is a special skill in the skill tree for summoner call subclass grow up. With that being said. you can easily level the other subclass cause this will give the sub 100% exper that you get from the main class summoner. Ex. Summoner gets instant 1,000,000 exp in one shot from the tiger dragon (lightning silver tiger rare creature) not only does the summoner get 1,000,000 but your sub get the full 1,000,000 exper, it is like killing 2 birds with one stone. Unlike the other main classes your use like say you had hunter as your main class and then fighter as your subclass, your main class hunter will get the 1,000,000 exper but the sub fighter will only get a small potion of that experience points. So that is why the Using the Main class summoner because of it unique skill tree ability called: subclass growup that give you 100% of the experience points also to your subclass making it real easy to level up your sub class in no time flat. I hope this tip help yall out.

Hey, thanks for the tips. Looks like I`ll be leveling up my summoner as a subclass now, until that specific skill unlock.

Btw where is the enemy spawn location that you mention? Forest, Volcano, Tundra etc? Do I need specific level requirement to make it spawn? Or specific item etc? Thanks for the help

@r093r10 it spawns randomly as a rare spawn, particularly in Advanced Quests, but not exclusively.

If going thr AQ route, it does not have a chance to spawn on City Area.

To add to OP's tip:

When you complete dailies/weekly missions, turn them in on a subclass you want to get to level 40. It is a massive amount of XP that does not diminish (meaning it is fixed, not level dependent).

When you unlock the client orders upstairs from Joseph and that person next to him, you get to run "trials" that are worth 100K exp each. I completed them on the required class and then turned in the client order after switching to a lower leveled class to give it the exp instead.

Some of those COs have a second quest worth 200K exp.

Tiny things like this speeds up your leveling, the goal is to get all your subclasses to level 40 so you can go straight into VHAQs at +50. You can easily get to level 50 from 40 in 2/3 runs (depending on your exp boosters used)