Finally realizing that the two in front of him are paralyzed somehow, Kuma spins to face the new threat, anger...still under control...flickering in his eyes. With a bellow of challenge, he charges at the crossbowmen with unnatural, horrifying speed, carrying his shoulders low and his arms trailing behind him...the blade of his sword nearly dragging along the ground.
He ignores the two crossbowmen completely, passing directly between them towards his true target...the mage beyond. Upon reaching him, Kuma raises his sword with all the momentum of his charge, letting the heavy blade swing up and around in a curiously graceful pirouette.
(Cheeeeeyarge! Activating Boots of Speed as a free action this round. This assumes, of course, that the mage is 140' away or less, and that there's at least one square between or around the two crossbowmen for him to pass by them. Since they haven't got melee weapons they don't threaten their areas. Adjusted to hit roll is +18, using 5 Power Attack for a total of +13 to hit the mage, and 2d6+21 damage should it connect.)
(Note - if the crossbowmen can't just be run past, he'll use Improved Overrun on one. Strength check to knock one prone is 1d20+10, and he can move up to 70' total while overrunning. Sadly, this means no melee attack on the mage this round, though he'll move to threaten the mage if possible.

)
(Sorry if this seems complex...I'm not clear on how far these guys are away (though assuming within 30' for ranged sneak attacks), or placement, so I give alternate possibilities rather than taking time for clarifications. Hope that's okay.)