There's 1. Squid 2. Infection 3. Alter ego 4. Split soul 5. Herobrine 6. Born that way
I wonder why! Its ridiculous how people say "SQUIDS FAULT" Because squids aren't SMART enough. Herobrine is "MEH" because there are stronger ways to KILL notch/tale over Minecraft/Both
Infection is not good enough because it doesn't seam right. If there was a infection that infected others and the SAME infection made Deadlox "Enderlox", there would be MORE people like Enderlox instead of one.
If Deadlox was BORN as a Ender Dragon hybrid or made like that at a young age, people would notice A SHIT TON FASTER! Unless he NEVER went out of his house.
The best one is Split soul/Alter ego. This is the best choice because the ego or other side could be controlled, and could only take control of Deadlox for a short amount of time.
There. I'm done. I think the Spilt soul/Alter ego is the one.