Welcome to EBN @SeattleRadChick and Thor.
My gosh...how I know this is frustrating. It sounds like Thor is trying to establish the "Alpha" male dominance rule over your other kids. I have no experience except for what I do with Jewel and Bentley. Jewel really acts out if she does not get enough attention. We try to spread the love around evenly but that does not work all of the time. Jewel and Bentley get into scrapping with teeth, snarling, etc. All we do I break it up.
You may want to see the advice of a pet behaviorist. @agingermom is in your area and might have a suggestion and I will tag @bullmama , @2BullyMama , @ddnene , @dolphin , @Marine91, @Vikinggirl , and everyone else who I have not mentioned.
You are not alone here at EBN. Someone will chime in.
Again welcome to the site.