The campaign in Clone Evolution is the main way to level your commander.
It offers some great rewards from Auto-battling and completing certain chapters. These include: Clone Fragments, iRobots, Bounty Bullets, Fiber, Ore, & Blue/Purple/Yellow Gear.
You can also pick 6 heroes for Auto-Battle and they will automatically gain EXP.
Completing chapters will unlock the Auto-battle for that chapter.
Auto-battle provides EXP and rewards even when you’re offline. It has a cap of 8 hours though, so you must login and manually claim the rewards or you will earn nothing beyond those 8 hours of auto-battling.
Unlike similar games in this genre, there’s no energy system in Clone Evolution, so you can attempt the campaign chapters as many times as you want. If you fail a battle, trying it multiple times can eventually result in a victory due to the RNG nature of many heroes and abilities.
There’s currently 4 different tiers of the campaign; General, Elite, Legendary & Epic.
Each tier has 50 different chapters, and each chapter has 5 levels (4 trash, 1 boss).