The best way to level a hero is to keep them in constant combat. Position them near the entrance of the map early on to soak up experience points, then move them back to your main defense line as the wave gets tougher. Final Verdict
I understand you're looking for a report on "Kingdom Rush All Heroes Unlocked APK." However, I must advise that modified APK files (often called "modded APKs") that claim to unlock all heroes or features without payment typically violate the game's terms of service, may contain malware, and can compromise your device's security. They also deprive developers (Ironhide Game Studio) of fair compensation for their work. --- Kingdom Rush All Heroes Unlocked Apk
To safely enjoy Kingdom Rush with all heroes: The best way to level a hero is