After hearing his quotes…
Jago: How does it feel to meet your god?
ARIA: I can play your game too machine!
Tusk: Your immortality ends here!
What can you imagine him saying…?
Sabrewulf: Your suffering shall end by me.
Glacius: Once I’m done here, your planet is next.
Sadira: I’m the spider now… while you’re the useless fly!
Orchid: I’ll send you to hell to join your brother.
Spinal: Your wish is granted… DEATH!
TJ Combo: I’m the strongest fighter in the entire universe, fool!
Kan-Ra: To think you can control my kind, sorcerer.
Riptor: Hah! Pathetic lizard.
Omen: You now dare to defy me!?
Kim Wu: You were chosen to defeat me? HA! They chose (unwisely or poorly?).
For Omen I could see him saying something along the lines of “I have no further use for you, begone!” or something along those lines.
Sabrewulf:I pity your life. Time for it to end.
Glacius:Once I am done here,your planet is next.
Thunder:Your brother? You will meet him soon enough.
Sadira:You will be crushed like a spider.
Spinal:You will finally get your wish,death.
Fulgore:You will share the same fate as the rest.
TJ Combo:Your punches can’t reach me. Mine on the other hand…
Maya:Shame you will never meet your sister. She is alive. Not that you need to know.
Kan-Ra:Your madness led to your doom.
Even though guest characters aren’t part of the canon, I imagine these…
Rash - Your party is over, amphiban!
Arbiter - Your journey has come to an end. It’s time for your martyrdom!
Anyone got other quotes to fill?
Wulf: I will grant you the release you crave.
Shago: Annihilation… Hah. You will learn the true meaning of that expression. (as he uses shadow oblivion into shadow command grab)
TJ: You disappoint me, champion.
Maya: Your search for your sibling ends now.
Daggers? Curses? They mean nothing to me.
Kan-Ra: Your powers are false hope against my supremacy.
Aganos: You are merely a pebble in my path, your fighting days are done.
Hisako: You will rejoin your family in agonising death.
I know guests aren’t part of the story but oh well:
Rash: I WILL unclog the frog. (said as you see Rash turned to stone and, in a new twist on the Agano stage ultra, shattered by a single tap of his finger)
I’ll edit some more in later if I think of any