I've designed loads of characters, most remaining in my head, some being written down on paper and others even having the honor of being in a book/short story. I'd like to pride myself by saying I'm good at filling in all details and having a full picture of who my character is and all other important details... If I had inspiration for them in the first place. If, on the other hand, I know I need to make a character, but I haven't had any 'wow' moments or vibes as to who they are, it's a real struggle for me to make them.
In the current book I'm planning, I have my main protagonist (designed and fine) who meets a travelling companion in the first chapter. They then stick together for the rest of the book and grow a close relationship (not romantic). Problem is, I've focused all my energy and time on developing the main protagonist and have now realized I know next to nothing about the other incredibly important character.
I have scene ideas and a rough plot line which I know how to incorporate him into, but if you were to ask me the classic basic questions for OC making, I wouldn't be able to answer them. I don't have background, motivation or even clear-cut strengths and weaknesses. But as mentioned previously, I'm really bad at making a character unless I have a clear idea in my head.
I have tried doing those sheets where they give you a scale, 2 antonyms either side (intelligent vs. dumb, etc.) to try and map out who he is but a) I never get far because I don't want to set in stone someone who I can't envision and b) the sheet doesn't make his character any clearer to me.
What do I do? How do I create a solid backstory? How do I create strong motivations? How do I do what’s normal when creating a character whilst adding him to an already made story?