Why mobs don’t block me the way? Is this a bug or a feature?
Its by game design.
For some reason EHG have decided collision detection isn’t required, personally I think it’s a big mistake as it makes some gameplay utterly implausible, but they’re not alone in this poor choice. 
I’d prefer if there was collision and then adding in a way to remove it as a defensive tool would be nice.
Even if collision pisses me off and gets me killed in other ARPGs, it makes more sense than phasing through everything just because.
But I won’t complain about not dying to being body blocked.
Yup, my time travelling magic user is totally pissed off that such an unrealistic thing can happen.
I like not being blocked. But on the other hand, it might be cool if you were blocked but have to use a traversal skill to go through them.