So my adventure character is about to go fight a Bronze Colossus. Is there anything I should know or do before I go to fight? My character is an Axeman, who is fairly good at ambushing if that helps.
Almost certainly you want to throw things at him. Throwing is kinda weird; it doesn't usually do a ton of damage but it's extremely high variance. There is one well-documented case of an adventurer killing a bronze colossus by decapitating it with a thrown fluffy wambler; obviously this is pretty unlikely but throwing rocks at it will eventually kill it.
Getting into melee with a bronze colossus is much less random... and that's bad for you, because the BC is many times your size and strength. You're probably faster though so just stay away.