There are three different methods you can use to level your units:
1) Grinding Quests (2-7 or 43-6 depending on your level of activity)
2) Enhancing with feeders/goddesses
3) Taking advantage of eventsGrinding Quests
This is the simplest, but also most time consuming method for leveling your units. Assuming you have a life (and most people do
), maxing out your units this way will take a while. To get an idea, you can use Kadaan's Easy Enhancing Calculator, but to summarize:
|Level||1 to 80||1 to 100||1 to 120|
|Time (2-7 Runs)||10hr 23mins||17hr 56mins||30hr 31mins|
|Time (43-6 Runs)||23hr 40mins||40hr 55mins||69hr 40mins|
So...yeah...not exactly the best way to level your units...Enhancing with Feeders/Goddesses
To supplement your grinding, you will want to take advantage of the game's card enhancement mechanic to level up your cards. This will greatly speed up your leveling. Feeders come from a few sources:
1) Brave Packs (1*/2*/3*)
2) Training - 26-5 is usually recommended due to the high Yakov (2*) drop rate and the occasional Catoblepas (3*)
3) Crisis Training (3*) - These pop out now and then during certain events, and are a good source of 3* feeders/monsters.
4) For Spenders: If you buy a lot of packs, you'll probably have a huge supply of 4* cards lying around for use as feeders.
5) Buying maxed (Lv80) or half-maxed (Lv40) 4* feeders.
Usually, you will level your cards using a combination of grinding and enhancing up to a certain point (a matter of personal preference) before you decide to do the rest of the leveling with goddesses.There are some recommendations when it comes to preparing feeders (which you can find by searching around the forums). If you intend to use maxed 4* feeders, they currently go for about 2-3te each, and there are recommendations for when to stop using them and to switch over to goddesses as well.Taking Advantage of Events
There are a couple of events of note:
1) Panel Events: Panel bosses provide good exp, make full use of them.
2) Training Events: Arguably the best type of event for leveling your units, but you'll need powerful (6*/7*) and active allies to help you kill the bosses.
3) Special quests/battles during events: These are rather situational - they tend to give good exp, but have a long (10-15min) cooldown. Using te/pots to grind in these quests/battles probably isn't the most cost effective way to level your units (unless you are competing in the event and will be burning them anyways).