As there are all kinds of heroes, there is also all kinds of criminal.
There are criminals who have their own codes and they are also criminals which is the run of the mill psychopathic cruel criminals.
But one thing that unite them all is their sins.
Loki lack that.
Hence, the Multiversal Convergence, the cause of probably tens of thousands of people dead, that is quite a sin.
A bloody reputation is created. If fame makes a hero, then infamy created a villain.
The sins provided him an in to the inner circle of the Crime Alliance.
It is lucky that the Multiversal Convergence was happening at the same time as the world began to expand.
The expansion of the world causes the population to not be concentrated at one place and there is the fact that Death Monarch had quickly repels the Otherworlders invaders with his magical means.