Espers are used mainly to bot in game, allowing the time requirement of high levels to exist without the frustration of the grind itself. Apart from giving the ability to bot through grinds, espers also add a dynamic to the game by making the esper itself like a second or third part of the character. The espers have different levels, just as the players characters does, except espers can only be leveled to 1/5 of the players current level. They also have various skills, which are a compliment to the players abilities, which also have different levels of effect. Thirdly, espers also allow the use of skyblades, giving you the ability to fly to avoid aggro.
Botting with an Esper[]
To start botting with an esper, the esper energy (located at the top of the first esper skill bar [red bar]) must be atleast half way full. The first 2 slots on the first esper bar is for esper skills only. The third slot is the slot used to use health potions in the game whenever a players health fall below a certain level. The fourth slot is used to replenish spirits via spirit potions, and the fifth slot is used to replenish esper energy (mainly lunarshade stones). In the sixth slot you will find a double sided arrow. This is used to bring up the second esper skill bar. It is in this skill bar which you can place the skills you wish to use during botting. Lower numbered skills on the second esper skill bar take priority to higher numbered skills.
Also on the second esper skill bar, you will find an icon that looks like a open hand. Clicking on this will allow you to set the skills portion of botting. In this top portion of the panel, you can specifiy when you want potions to be used and a minimum time (seconds) in which to use potions consecutively. So if you set HP% to 50 and seconds to 5, it will use potions once the players HP falls below 50% and in the case that the characters HP doesn't raise fast enough, it will wait 5 seconds to use another potions. These are extremely critical. Trial and Error with each set of enemies is the best way to figure the optimum settings. The default settings work for most of the monsters in the early stages of the game.
In the middle portion of the panel, the setting for which drops to pick up during botting sessions can be specified. You will need to type in the names of the items that you want to pick up exculsively, or not pick up at all. The setting are pretty much self explanatory.
Further down, the bottom portion of the panel contains the skill timers (in seconds) for each of the skills that were placed on the 2nd esper skill bar. It is according to this time in which you will use the specified skills during the botting session. Obviously, the lower the time, the more the skills will be used. If you do not wish to use any skills at all, you can dot the "Disable Skills" box right above the the skill timers.
Once all the setting are set, you can click on the sword icon to start the "invigorate" mode, which will bot for you.
Leveling an esper[]
To level an esper, the player must use the esper skills, which will add 1 experience point to the esper itself. You can check the status of the esper by mousing over the orange bar under the esper skill bar. Once this bar reaches its full capacity, you can take the esper to esper mystics, to increase the level of it. Each new level will give added bonuses to the esper, which will also be added to you.
Flying with an esper and skyblade[]
To fly in the game, a player must have a skyblade and esper equipped, and the esper energy bar must be at 100%. Once all of these requirements are met, a player can fly by clicking on the wings icon located on the extreme right side of the top esper skill bar, so long as the player is not in combat or riding a mount.
During flight, esper energy is used at a rate of 2 energy per second, and once it is completely drained the skyblade will turn off and the player will fall straight down to the ground. The fall itself does not damage the player, but falling into an area crowded with aggressive monsters may lead to the player’s death, especially since the aggressive monsters will prevent the player from activating the skyblade again until the player escapes.
Leveling An Esper's Unique Skill[]
The skill that you use to increase your espers level also has its own ranking, like a normal skill. To level your esper skill, you must use a Tawen Gem. These can be found in the Cash Shop and cost 1 Gold Jaden and 50 Silver Jaden each. This is just like refining a piece of armor, it comes with chance. You may need to use 5 or 6 before your esper skill becomes level 2 or higher.
To add extra faction skills, you must use the Gem that corresponds to your faction. For example, a Lupin player would use a Lunara Gem. These can be found in the Cash Shop for 5 Gold jaden each. What these ones do, is they replace any learned or unlearned skills you have added with random faction skills. For example, say you had an esper with these skills;
Chi Bottle (Bonus Skill) Masterful Acceptance Lvl1 [Unlearned] Frost Blade level +1 Faithful Defender +1
If you used a Lunara gem on this esper, this could be one of the possible outcomes.
Chi Bottle
(Bonus Skill) Masterful Acceptance Lvl1
Thicken Blood level +1
Hazy Blur level +1
Doing some of these things can greatly increase your espers level and skills, but it comes at a cost. ;)