The best fighter in each novel is often ambiguous and unclear, with the exception of Sweeper Monk being the best in DGSD and Shi Potian being the best in OTG, who do you think is the best in each respective novel? They have to appear in the novel to count, so no WCY for LOCH or YCZ for DOMD etc. Here are some candidates, you can add someone if you think I missed them.
LOCH - Ouyang Feng/Zhou Botong
ROCH - Guo Jing/Yang Guo*
HSDS - Zhang Sanfeng/Zhang Wuji
SPW - Dongfang Bubai/Feng Qingyang
BXJ - Mu Renqing/Yuan Chengzhi
DOMD - Gui Xinshu/Jiunan/He Tishou/Hong Antong
ADS - Di Yun/Ding Dian
B&S - Yuan Shixiao/Tianhong/Tianjing/Afanti
FHWZ/XSFH - Hu Fei/Miao Renfeng/Chen Jialuo
*It is not necessarily my intention to bring up this debate again.