Any manga where the mc is evil like person. Like he or she doesn't care to beat the shit o...

ff.
http://www.mangago.me/read-manga/boss_in_school/

he's not really a bad person though, but he's powerful.

http://www.mangago.me/read-manga/nidome_no_yuusha/

http://www.mangago.me/read-manga/sasori/
http://www.mangago.me/read-manga/baptism/
http://www.mangago.me/read-manga/master_of_gu/
http://www.mangago.me/read-manga/tomodachi_game/
http://www.mangago.me/read-manga/nidome_no_yuusha/
http://www.mangago.me/read-manga/fukushuu_kyoushitsu/
http://www.mangago.me/read-manga/a_post_apocalyptic_journey/
http://www.mangago.me/read-manga/kaifuku_jutsushi_no_yarinaoshi/
http://www.mangago.me/read-manga/circle_zero_s_otherworldly_hero_business/