Still Waters is the only one that will do a traditional fist fight, while Mancomb and Colossus will give Geralt other ways to beat them. Having the Protection Glyphword as your armour enchantment will apply the same automatic, stamina-free, Quen shield to you upon entering combat, therefore gaining a decent advantage during this and any other fistfight.
For Mancomb, he will do a battle of wits in which Geralt must match his rhymes. Simply pick the rhyming line 3 times to beat him.
For Colossus, he will ask for Geralt to parry him, as nobody has been able to block his punches. He will double Geralt's bet if Geralt accepts the challenge to parry him. Simply hit the parry button just as he's about to hit to block him. Once he's been parried 3 times, Geralt will win the match. Geralt can also refuse this parrying challenge and propose to fight a traditional match, without extra bet.
- While traversing Toussaint, Geralt learned local aficionados of wine and raucous entertainment were fond of organizing fistfighting tournaments as well. He decided to enter the lists.
- The witcher defeated a triumvirate of challengers. He told me later some of them were quite colorful characters!
This feat qualified him to fight in a bout against the reigning master of the Toussaint fistfighting circuit.
- Defeat Colossus in a fistfight. (100 parrying 3 blows)(100 for defeating)
- Defeat Still Waters in a fistfight. 100
- Defeat Mancomb in a fistfight. 100
- Mancomb's name and appearance is a reference to Guybrush Threepwood from the Monkey Island series, in which rhymes and insults are often part of combat.