At the end of the road? I loved the uke for standing up for himself and showing the bullies what they deserved.
Slave B
not really bullied but more of looked down on + historical and underrated do give it a read! (づ￣ ³￣)づ
http://www.mangago.zone/read-manga/legend_of_the_northern_blade/
http://www.mangago.zone/read-manga/life/
Trigger warning tho. This one shows self harm, sexual assult, fucked up bullying etc. But the main character gets a looot stronger mentally.
any manga/webtoon when the main character is bullied but gets stronger and fights back later on. Like Lookism or How to fight (=・ω・=)