One of the keys I discovered to making a good character is knowing where they grew up. You have to create that place. What are the average life experiences of someone who grew up to age 18 or 21 in ancient Rome? Old Britain? Pre-Columbian America? Most games don’t show you that. If you want to make a realistic character, you need to start by researching and building that first. That is probably the deepest art to true character designing. We didn’t just roll dice, generate a random character, and hope for the best. We built a person with a real childhood, and then added in their actions in the game before testing them to make certain they wouldn’t go off the rails and flip out the moment we turned them on.