Here's Lignite as Asriel Dreemur! (Did I spell it right...?)

On the Genocide Route you wouldn't interact with him for the most part, but on Pacifist, playing as Emerald will allow you to encounter Lignite as a Bossfight and will give you the Pacifist Ending.

#Mobitale

(And just like the 7 souls, the 7 Chaos Emeralds will represent those in his last form, with the Master Emerald in his chest)