I am not sure if they are the creators of it! I just have seen them play it!
Quick explanation on how it works for those who havent heard about it:
So both way of playing have terminals for every number on the wheel
Karl’s way:
you are getting the last number so lets say its 7, and you do +1, +2, +3, -1, -2, -3 (if you want you can go up to 10). so for example 7-2=5, terminals of 5 are 12, 10 so you play 12, 10 with 3 neighbors.
Shadow roulette way:
you are getting the last 2 numbers. for example 25 and 7 were the last 2 numbers. So you do 25+7=result or 25-7=result and than the result+1, +2, -1 or -2 and than we get the terminals
the idea is to wait for a winstreak and high hit rate.
lets say (+ and -) (25+7-1) had played for the last 3 rounds and have 70% hit rate, so you play it.
Forgot to mention i have made program for both version if anyone want to try play it. Also if you have data for the wheel you play on (200-500 rounds) i can give you analysis and than you decide if its worth playing.
I know Karl, talked with him few times in skype . He is not player , he is casino affiliate and his job is to do that more peoples will come to online casinos and will lost more money.
All what you describe is system . Similar systems are thousands and everybody can create them…plus that is far no main Karls way which he promote in his videos…
Cant confirm about karl i cant really find who the real one is… There are a lot of people impersonate him and trying to scam. I just found old video if his explaining how to play his system. I enjoy it thh but a bit risky and luck depending
I have a friend who many talked with him and even bought his system ( friend is also a system player ), but no benefit from that - lost even more…
Karl said to me that he was not in any land casino and did not know any German AP player, he only did that job that was given to him by the casino - so he is on the other side of the barricades 
Vos sos un payaso al igual que sereja , jugas firmas y cuestionas a todos. No sos ejemplo de nadie.haces tu negocio aca . Sos un don nadie , y te lo dice alguien q gano y gana mas que vos. No voy a revelar tu metodo de mierda con el q supuestamente nadie te supera ajaajjaja.80% de ventaja tuve yo
I am not sure what method shadow roulette use but i have my own way of playing and different conditions can cause number to shift around the wheel and previously negative numbers can become positive and vice versa. Conditions are like wheel speed, dealer spin, ball used, tilt of wheel and also air pressure and cleaniness of wheel.