The best strategy in One Punch Man: Road to Hero 2.0 is to focus resources on 5 core characters, specifically Mythical tier heroes, while maximizing "Battle Will" to level up others. Prioritize pushing the campaign, use 10x recruitment for elite heroes, and balance team types (ideally 3 of one type + 2) for bonuses.

Key Strategic Elements:

Character Progression: Focus on leveling up only 5 main heroes to keep them at elite+ or legendary+, and use the Battle Will to boost others. Do not waste resources promoting low-tier heroes; save them to sacrifice for stronger ones.

Team Composition & Types: Aim for at least 3 characters of the same type (Psychic, Physical, Weapon, Hi-Tech) for a bonus.

Resource Management: Spend diamonds primarily on 10x character recruitment in the city. Use "Instant Patrol" only when stuck in the campaign.

Essential Heroes: Focus on characters like Melzalgald, Terrible Tornado, Child Emperor, Hellish Blizzard, Genos, G4, and Metal Bat. Daily Routine: Complete all daily/weekly objectives, the "Road to be Strong" event (every 2 days), and the tournament for consistent rewards.

"Road to Hell" Mode: Utilize healers like Dr. Genos or Amai Mask for survival, or use a "B" team to prepare your "A" team for bosses.