Blood trickled down from Leon's head and cascaded down while tainting the back of Rex hand that was still grabbing his face. However, even though Leon inflicted a huge blow from him, a tip of a dagger lightly poked Rex side.
If Rex just heedlessly thrust forward, he was certain that he'll also receive a grave injury. After all, facing Leon needed precise calculations before attacking him as he was insanely flexible in terms of a bloody fight.
Thanks to the years of working with him, Rex grasped a few habits of Leon when fighting. Yet, Rex must admit that he lost. That until now, he never defeated Leon; not once. The only reason Rex successfully landed his attack to him was due to Leon's consent.
For a split-second, Leon completely drop his guard as if giving him all the openings. Hence, with a great mind and keen eyes of Rex, he didn't wasted the once in a lifetime opportunity.
heya! explaination why Rex and Leon fought will be explain later :)