The ultimate battle

When Ren was travelling trough some ancient ruins the sky suddenly turned black a high level demon appeared he said you are dangerous you should be eliminated he attacked

 Ren but Ren dodged just barely Ren fought with everything he had his black phoniex regeneration was struggling to keep up even worse his newly awakened 

 BLUE POISON couldn't even do thing against the demon after lightning for hours Ren said :- ok I will give it everything I have just before I kill you can I ask your name or who send you DEMON!!!!! 

THE Demon said :- I don't have a name to give to a catastrophe like you little boy then

 Ren said OK you asked this yourself Ren backed up a little the demon tried to attack but he couldn't because the blue poison finally took it's effect and paralyzed the demon for 10seconds Ren took raikkoku a little back then he forced everything he had boom suddenly he awakened black lightning then Ren charged everything his speed surpassed lightning itself then Ren teleported infront of the demon he slowly said tempest flash then

 he instantly beheaded the demon and then he collapsed but deep in the dark the same chilling prescence said hmm... interesting while in hell we saw a demon black pupils red hair saying so you have returned master...