A tiny omake. Cause hell, this looks like that time N***ndo decided what B*wser wasnt enought of sunday villain and they introduced M**io Evil Twin^tm! - Wa*uigi!

Cain: "I must tell you... i have an Evil Twin^tm!"
Everyone: "Oh... that would explain some things..."
Cain: "His existance is tormenting me each and every day. The thing he do... They leave me sleepless at night..."
Everyone: "this would explain why Imperium suddenly started to portrait Niac as Cain arch-nemesis!"
Cain: "His name is Niac and he is most vile, corrupt, degenerative brother a person ca... Wait, did you say "Imperium has him as my arch-nemesis"?"
Everyone: "Erm... yes. He just got assigned a punitive role and is supposedly, working on gathering forces to fly here and kill you in personal combat."
Cain: "Well, we have nothing to worry about then."
Everyone start singing: "Sasuga, Cain-sama! Hail!~ Hail!~ Commisar Cain!~ Hero of Liberation!~"
Cain, inside his own head: "Niac... i know i was the better twin... but for Imperium to fall that down... to assign my own brother be my killer... They truly have fallen. They must be high as kites to make my lazy, unorganized, scatterbrained, unmotivated brother to do anything... But then again, last i heard about him he was visiting some weird-ass planet under... Tau? Ugh... it was too many years..."

~~~~~~~~~~~~~~~~~~~~~~~~~~~~19 years later~~~~~~~~~~~~~~~~~~~~~~~~~
Niac, the "Evil Twin^tm!" inside his own robot suit: "Cain... i have come to 1v1 you in glorious mech combat! My firesuit is better than your knight! Look at this glorious gauss-cannon i have! And this blade! I named it She'Wras, after my first girfriend!"
Cain, massaging sides of his head as absolute HERESY of his supposed killer\brother\hero of Imperium as Niac pose in xeno knight-suit and brag to all to hear about his xenophilia: "Niac... you are "Imperium hero", right?"
Niac: "Frakk yeah! I was sent by something or different branch of Inquisition on a quest to kill "Black Commisar" who poses great danger to all of humanity! So lets 1v1 in mechs and overcome any hurdles with power of shonen-manga! Then we will be back to kick-ass adventure of killing goblins and orks for loot and fame!"
Cain, stealthily pressing button to inject himself with dose of panacea^tm: "Niac... Imperium abhores anything xeno. HOW did they let you get that mech and have a xeno girfriend?!"
Niac: "Ah... That... Ehehe... Many thing happened and i might or might not keep spacing Empire Inquisition delegations when they try and fail to kill me. After all, they should stop being total idiots who think that attaking a dude in mech suit while armed with handheald weapon is a good idea. I mean, there was that episode where one of them tried to stuff a singularity charge in my suit but he forgot it has personal shield arrey... Or that time one of them tried to use melta-gun... Anyway, what is important... I found what i like to do in my life!"
Cain: "And?"
Niac: "Its killing orks and bangin xeno chicks! YEEEHAW!"
Cain, facepalming hard: "And this is "Hero of Imperium"... Emperor... WHY?! What next? a frakking primarch will run away from Emperium with his xeno girlfriend and..."
*Eldar warpgate manifest on the Centrall Park where Cain and Niac are meeting and out walk eldar with a figure Cain thinked he will never see in his live! An Emperor-own son! A primarch!*
Eldar women: "I foreseen future and saw this planet becoming a good place to start family, so here we are! How about this, mon... Honey?"
Cain, cough blood and fall on all four: "Emperor... give me strength... for my sins are many and my flesh is weak... Guide me in my times of trouble..."