Billystorm 
"[@TheSultanAkbar":](/images/2556970#comment_9526075
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That does make sense, but the way the comic presents him after his transformation is, well, nasty. Sealing away his umbrum elements is supposed to make him a better pony, not to completely change him. Don't know if I'm reading too much into the comic, but to me it looks like his demeanor has completely changed after the purification/transformation. He lost most of his defining features.
My headcannon is similar to yours. Together the princesses and Hope sealed his umbrum elements away, just like when he was a colt it won't easily resurface. With Hope by his side he can always feel at ease., less of his former grouchy self and more of a calm, collected pony living his best life.
yeeeeet
That does make sense, but the way the comic presents him after his transformation is, well, nasty. Sealing away his umbrum elements is supposed to make him a better pony, not to completely change him. Don't know if I'm reading too much into the comic, but to me it looks like his demeanor has completely changed after the purification/transformation. He lost most of his defining features.
My headcannon is similar to yours. Together the princesses and Hope sealed his umbrum elements away, just like when he was a colt it won't easily resurface. With Hope by his side he can always feel at ease