Thanks for a fantastic question! Our personalities are partly made up from the things we feel, so anything that can affect our senses ‘may’ affect our personality. Also people’s personalities are not always the same throughout their lives – the same person can be cruel at one point in their life and caring at another time.
There have been cases of brain damage that cause specific personality changes. For example damage to the frontal lobe can cause or prevent people from inhibiting some actions that aren’t socially acceptable (like bullying people). There is a famous case of a man called ‘Phineas Gage’ that you should be able to read about online, apparently lots of the facts in this case are not correct, but the idea was that after getting his frontal lobe damaged from a railroad spike his personality seemed to change.