Well... i'm not sure about the tipe of strength that you're talking about...
fisical strength? intelligence? ability in solving problems?
But i hope tha one of these is what you're looking for:
http://www.mangago.me/read-manga/may_i_ask_for_one_final_thing/ (this MC is a real badass in a matter of fisical strength)
http://www.mangago.me/read-manga/when_i_woke_up_twenty_years_passed/ (this MC is really capable and basically good at everything)
http://www.mangago.me/read-manga/dad_is_a_hero_mom_is_a_spirit_i_m_a_reincarnator/ (this one too.. shes the most clever, the best with magic and super overpowered)
http://www.mangago.me/read-manga/i_m_a_villainous_daughter_so_i_m_going_to_keep_the_last_boss/ (this MC is really capable and solve most of the hero's problems)
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Thank you so much! ヾ(☆▽☆)
Heyo guys!! I need your helpヾ(❀╹◡╹)ﾉ~. Can you please suggest mangas where the MC is stronger than the hero? Like they have been reincarnated/reborn/summoned on another world and they're actually stronger than the hero after their first kill or something like that?
Many thanks!! ヾ(☆▽☆)