That Soul Reaver kinda catched my attention so i went to see if it had any drawback and not even to a suprise it actualy does. Here is one that would be fitting this duel.
Taken directly from gamefaqs.com
"The Soul Reaver has a mind of its own. It is in charge, not
Raziel. See that nifty little circle slowly working its way around the health spiral? Well, if it manages to form a complete circle, the Reaver takes control and saps Raziel's health, returning him to the Spectral Plane."
Considering that Sonic can deal with all ranged attack using Insta-Sheild and you seem in insisting Raziel would just vanish before blow. Here is the weakness of the Soul Reaver that i will use.
When Sonic cant kill something directly he avoid it run arround and wait to see a weak point or if he couldnt use his enemy power against him. So Sonic would simply avoid melee combat and the Soul Reaver would consume Raziel.
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