All My Cultivation Depends On Exploiting Loopholes

*He had transmigrated into this isekai for so many years, All his could remember was that he and his sister were an orphan. 
And they were picked up by an elder of this cultivation family. 
When he first came to this world, he thought that he would be invincible, but the cruelty of reality gave him a heavy blow.
His cultivation talent was so poor t…
Two years ago, When the elder had passed away, Those people of this family had started to dislike him.
And things are getting worse
The more beautiful his sister became, the more those people who had bullied them began to think about her beauty.
Among them, The one who had the strongest cultivation talent had start trying take his sister away from him！
Even though he had no talent of cultivaion but His sister was his only family in this world, How could He allow anyone to violate her!
When that man placed his foot on his stomach and laughing at him and saying "It won't be long before you little sister of become my toy.” 
His resentment had finally been detected by the system!
“Ding! Host's resentment has been detected. War God System activated.”
“You can humiliate me, but you can't touch my sister!”
The System that I've been waiting for has finally arrived. How can a trash of the generation defy the heavens?
Those who bully my sister will die!